Is there an explanation for John Wick's behavior at the end of "John Wick: Chapter 2"?

Because D'Antonio strongly implied that he would simply never leave continental grounds, so that John would never get the opportunity to kill him without violating the rules.

D'Antonio: Duck fat. Makes all the difference.
Winston: Jonathan...
D'Antonio: Have you seen the menu here? Lot of options.
Winston: Jonathan, listen to me...
D'Antonio: A man can stay here a long time and never eat the same meal twice.
Winston: Jonathan, just walk away.
D'Antonio: Yeah, Jonathan.
Winston: Walk a-...
[John shoots D'Antonio]
Winston: What have you done?
John: Finished it.

It's quite clear that Dantonio was safe (he thought) inside the Continental and could stay there indefinitely if he so wished while at the same time, Dantonio could send wave after wave of assassins after John Wick.

Indeed, he comments as much in the movie and so Wick's only alternative was to kill him right there and take the consequences.

Dantonio: Have you seen the menu here? A lot of options. A man can stay here a long time and never eat the same meal twice.

He's saying, "I'm safe here and there's nothing you can do about it!".

Wick then proves him wrong.

John said why himself, he's "Finished it."

He wanted out of the reality of existing within that assassin's world and by killing a member of the High Table on the Continental's grounds, he was definitely out.

Now that his wife was gone and his house destroyed, even the sanctuary that he had created inside that world was removed, and he was intentionally severing himself from that old life.

It was a methodical suicide of a persona, but John Wick is not suicidal as a man, not in the least. He wants a chance to live a life like he'd shared with his wife. He ended the film by making clear that all of the assassin's and members from the world he had just irrevocably severed ties with know that he'd kill everyone single of them that tried to follow him into his new life.

Period.

The rules are contradictory. A high council member can conduct "business" on Continental grounds basically by sending a "bullet" via a contract by phone but John isn't allowed to put a real bullet in his head. There's a problem with that. Had John given Winston a little courtesy and followed his advice "John walk away!" Winston would have checked Santino by telling him "You can't order a hit via phone on grounds either. You have to leave" shutting the door on a grey area thus allowing John to kill him off grounds. I believe Winston was always on the assassin's side and respected order and as a seasoned "manager" would have made it VERY clear business of ANY type that regards killing be done on grounds.

What I think is that, at the end when Winston says to John Wick that he has one hour before excommunicado. Since the stakes are doubled all people in the park are alerted that they have a chance to claim the bounty amount of 14 million dollars before that one hour gets completed after which the contract is called off.

So that's the reason all the people are staring at John Wick and he is running to escape for the better of this completion of that one hour before he's considered persona non grata.

Please feel free to edit or comment if it's not answering the question.

A combination of rage for the house and for the assassination attempt on him. And the fact that John felt he had no other choice. So he did it on the spot. Plus like others said, it was his way of telling the Continental, I'm not part of this life anymore. So it was impulsive but at the same time deliberate, with a purpose. He wanted a new life, and he would kill anyone who tried to stand in his way of it.

His house was destroyed & everything that held the memories of his wife went up in flames. Her scent. The pillows on her side of the bed, even a few strands of hair that were still caught in the bristles of her hairbrush. When John walked past the living room, I can see him still seeing her curled up on their couch, her feet tucked under a blanket as she read a book & sipped hot tea. That card she had delivered to him along with the puppy was not his only keepsake. So, my belief is that was the last straw for him. I figure, temporary insanity brought on by extreme grief is why he disregarded continental rules.

Here is what I've written about what I hope Chapter 3 will be about.

John Wick goes underground to a rarely used safe house that his old friend, Marcus had. (William Defoe brief return in memory) Marcus had heard John was wanting to leave his current life after meeting and falling in love with his wife. He offers his “safe house” to think about what he wants to do. Will it be worth it? Is she worth it. Getting out will take a miracle. Because no one EVER gets out or has ever attempted to. John did stay at Marcus's safe house, but other images of her on his phone only strengthen his resolve. So, within two weeks, he made his decision and began planning.

THE MARKER:

Question: How did this particular person help John complete the “impossible tasks”

1. Intel?
2. Weapons?
3. Back-up men to cover his ass?

Flashbacks of the events that lead to those impossible tasks and the acts themselves.

THE CONTINENTAL:

The High Table holds an emergency meeting regarding John Wicks killing of Gianna and her brother who sought revenge for it. And within the walls of The Continental. They discussed Winstons allowing John an hour head start before calling Accounts Payable to label him as Excommunicado. Someone as dangerous and lethal as John Wick, should have been killed immediately for his breaking of The Continental's rules. AND now, they believe with no rules binding him and knowing everyone will be coming after him, then he has nothing to lose and may very well come after them. One by one. Questioning the leadership of all the Continentals around the world, they decide they need to step in to assist in overseeing each one to ensure that those who might be sympathetic to John Wicks plight, are encouraged with a violent message what happens to those who break those particular rules. After all, The Continental is meant to be a neutral zone and a safe house of sorts to those in this business. Even assassins need a holiday now and then to let down their guard. So, if someone like John walks in and decides this particular mark is too dangerous to be allowed to live and attempts to use The Continental as his/her permanent, safe house, as Giannas brother insinuated he would, which is why John shot him where he sat, then what is to stop others from following John's example. Anarchy would ensue.

Soon, the overseeing of the Continental causes a panic with those in the business. They are outnumbered and harassed as they try and check in or out. The High Table hires other assassins to build their own numbers to help with this. Winston is basically put on house arrest as is his Charon. The High Table fears his fondness of John and that he will help John through information about who is after him and suggestions of places to hide or will give bad information to get others off Johns scent.

JOHN WICK:

John has truly lost everything. His house was destroyed along with every picture, scent and being able to, in his mind's eye, see her curled up on their couch wrapped in a blanket, sipping tea while reading a book. The pillows on their bed that he could lay his head back on and hers laying just right there. Maybe a strand of hair, her scent still there. And poor Daisy in the yard where he buried her. His cell phone. Broken during the fight with Cassian. The video destroyed.

Everything is gone.

He had only wanted to stay retired and continue to attempt to live his life in peace while holding on to the memories of those few short years that were the happiest he has ever known. But, maybe everyone was right. Once an assassin. Always an assassin. How could he have ever thought he could fully escape it.

The marker. The Debt he owed. A situation with no end where he could go back into retirement. And now, he was on his way to Marcus safe house. A place that was so deep underground, that a person could stay for years. Safe. Solitary. Alive. What else could he do when thousands of others had received the same message. John Wick, Excommunicado. All John could do now is wait until the worst of the storm has passed and think of some possible scenarios that could help him live. The question is........Did he really have anything to live for? As for now, though, he is waiting. Focused only on keeping his body and reflexes sharp in the gym and sound-proof firing range that Marcus bunker provided. John thought of Marcus and missed him. He and Aurelio were the only two people he trusted. Yet, he knew that if he had gone to Aurelio that it would have put his life in danger and honestly, he had no time.

While John bides his time, he doesn't know how his killing Santino D'Antonio has turned everyones world upside down. The High Table has taken over every Continental all over the world. The High Table is powerful and has a very long reach and plenty of others to recruit who would rather be on the good side of the powerful instead of their cross hairs. Their concern is that others might follow John Wicks bad example and start to ignore the rules and sanctuary that The Continental provides. And they feared that with Johns abilities that he would decide to come after them. One by one. The High Table could not afford to have their members killed and leaving their chairs open. Those that are left, could very well use this to fight amongst themselves to completely take over and run the High Table as they see fit, which would be disastrous to have only one in charge of an organization so powerful.

3-6 Months?? Goes By. John quietly slips out of the safe house. Disguised as a blind homeless man he walks the streets of New York. Seeing one of the Bowery Kings employee. John quietly overtakes him and binds the mans hands and places a hood over the mans head. He drags him to the alley and behind a dumpster and questions him regarding all that has gone on in these past few months.

After John hears what his killing of Santino has created, he knows exactly what he needs to do but also, whose help he'll need to fix this. Even though, the help he will need comes from the very persons most affected by his actions. Winston. The Continental. He has no choice but to take the chance to see Winston and prays he'll hear him instead of shooting him the minute he sees him. He presses several coins into the mans bound hands and whispers a message in his ear to be taken to the Bowery King before leaving just as quietly as he appeared.

After he is released, the man waits 30 minutes before running back to his Kings Castle. He informs him of what had just happened. Looking surprised and laughing loudly. He says, “Well, well well. The Messiah has returned” He tells his informant to keep that information to himself and sends a message to only a select few of his people to attend a private meeting that night. “This is an interesting development, he thought to himself. And one that just might be very welcomed.”

John ends up “leading” the war against the High Table. And no matter what happens to him now, all that matters is the High Table is ousted from all the Continentals and order is restored amongst his fellow assassins. But the hardest to recruit was Cassian. The Scar on his chest was a constant reminder of how John had left him. Still angry and the desire for revenge against John for killing Gianna is very much on his mind, his hatred of how the High Table has taken over the The Continental is stronger. Rome and New York seemed to be feeling it the most due to the fight where he and John fell through the window and into the lobby in Rome and there was Winstons obvious affections for Jonathan. But, knowing that there is no way John would even attempt to sneak in to either one due to the massive security measure they put in place. And the High Table was gathering their followers and sending them to London, Paris, Argentina to safeguard the Continentals there. While others were searching for any possible safe houses and others who might be loyal to John that he could escape to. And upon going to Aurelio's place of business and even after roughing him up some, didn't reveal anything other than Aurelios employees working on Johns car. They figure, let them finish. John just might be tempted to come back for his beloved car.

At this point, the only option is for John to team up with a select few. Although, with The Continental and the Bowery King, that is actually more than just a few. Throw in Cassian whose grudge against the High Table is stronger than his desire for revenge upon John Wick. Their numbers start adding up.

After the War, the only recourse is for John to be Exiled completely from the world he is accustomed to. To be completely cast out of the garden of eden. An Untouchable. Which is different from what Winston originally had to do. Allow John to live but strip him of everything he had in that world. His passports, contacts, arsenal, special made clothing and the gold coins. Making John nothing more than just a Mortal Man. An Untouchable.

John Wick wants to retire and live in peace to continue grieving for his wife, then wish granted.

After the decision was handed down unanimously by all those who has replaced the fallen few of the High Table and the Management of all the Continentals, John is seen walking down a crowded street where not a single person looks at him except a curious glance here and there. John is no longer the "Man who is sent to Kill the Boogeyman" he is still going to be quietly watched to ensure that he isn't tempted to come out of his exile. But for right now, all those in the business has quietly slipped away leaving John to walk amongst regular people going to their normal everyday jobs and lives. As John walks with the crowd of people, his dog beside him and the necklace clutched in his hand, he hears a soft voice say, “Sweet dog you have there” as she briefly bends over to pet the dogs head. She smiles at him, a raised eyebrow to indicate she noticed the small injuries to his face before continuing on her way. John just stares at her for a second before simply saying, “thank you” before she had completely walked away. She turned her head slightly toward him and smiled, indicating that she heard his response before she disappeared into the crowd of people.

The last ray of light disappeared as the clouds took over and rain gently started coming down. John, though, didn't notice. He stood there staring in the direction the woman had taken . John then looked down at his dog. Squatting down, he then rubbed the pups head and asked him, “So, buddy. What should we call you?” John slowly stands up and with the slightest hint of a smile and possibly a glimmer of hope in his eyes, he tugs on the leash and continues walking on.

NOTE from the Author:

All that I had written in the first paragraph, I never saw mentioned on any media outlet. Which is sad, because this is an incredibly important moment. It goes back to Johns loss of his wife. John's heart was inside that house. In the Kitchen where he and his wife cooked their meals. The couch where they snuggled together while watching TV. The double sink in their master bedroom. Everything that held her scent, her clothes, her make-up. The images he carried in his mind of those years with her that lay on top of his memories of all that he had done over the years as a hired assassin. The massive amount of people he killed on top of that just so he could get out he and have these precious few years with the woman he fell in love with.

The way John Wick Chapter 2 ended left me stumped as to how in the heck Chapter 3 would go and would it be any good or completely ridiculous. Look at the Fast and Furious franchise. Where are they at now? Number 8? You know the saying, “Too Much of a Good Thing?”

The story for the first John Wick is what appealed to all of us who have special affections for Keanu Reeves. John Wick. Tortured, grieving, those emotions contained behind serious brown eyes. I believe that going further than Chapter 3 would take something very real that fans have felt in regards to the John Wick movies. Chapter 3 would have to have some type of final closure for him. And killing him would cause an uproar. I imagine, if there were an actual email/snail mail address that fans could write to and give their thoughts and opinions regarding the John Wick Franchise, then I believe you would be seeing many letters like mine begging you not to ruin the appeal of John Wick by taking away the emotional appeal that the first story gave us. He kills people for a living, yet, here we all are, cheering him on and feeling his grief.

From the interviews, it didn't appear as if John Wick Chapter 3 was very far into becoming a possibility. So, Keanu's ideas of a war between the High Table and Continental is the only obvious scenario for Chapter 3. But, what is Johns part in all of this? Because it more seems like its a three-way war between the High Table, Continental and John Wick himself. Yet, that wouldn't work.

So, tidbits of ideas that I wrote out stay true to the appeal of John Wick. His idea of right and wrong. Taking responsibility for his past decisions and the effect they had on others. The Bowery Kings sarcastic declaration, “The Messiah has returned.” Basically, means, John caused this shit to happen and only John can truly clean it up. And he and his people will help only because the High Table, The Continental and any other establishments, should remain separate from one another. Because if the High Table continues to grow stronger, where is their reach going to end?