Why didn't the key word trigger the hypnosis on the first incident?

I think it can be safely assumed this is a gaffe. It appears on a few sites online where it is identified as a Movie Mistake and there are forums over at Reddit and other such sites with people citing this issue as something that brought the film down.

I've yet to find a comment or response from the film makers about this, but like with any movie, there are tons of gaffes like this that slip through.

So this is a little stretch but could it be possible that Evans received a phone call while on the way to the safe and was hypnotized then? When Rhodes is interrogating McKinney, he says McKinney can hypnotize people over the phone.

I didn't realize that others didn't pick up on this till I saw this post. So I'll post what I picked up on when I watched the movie. While at the warehouse the guy who helped load the safe said......"sir you got a phone call and said Washington wanted the safe moved." then the guy said "you never heard that come out of my mouth agent." it's at that point that Dylan realizes what happens and tries to stop him from saying bs which if you didn't catch the exchange you would wonder why he would try to stop him cause there was no one in the warehouse that was in the audience in Vegas. Cause thats the trigger word that triggered the french guy to play beethoven and not the trigger word from new orleans which was freeze to tackle the quarterback..so it would seem that bs wouldn't trigger anything but knowing that Merritt can hypnotize over the phone and guessing thats hes gonna taunt the FBI guessed that bs was going to trigger some sort of reaction which is why he said he guessed it was Beethoven...but in all reality now knowing he's the puppet master we know he told them to call and hypnotize his boss.....Anyway that's what I picked up on...I could be wrong but...