Dwight and Sprinkles in S04E01

In season 4 ep 1 of The Office Dwight kills Angela's cat Sprinkles.

The general motivation makes sense, Dwight has a farmer's mentality and wants to put the sick animal down. However at one point Angela tells Pam that she found frozen food bags torn apart with her cat in the freezer. That tells me that Dwight put a live cat in the freezer and that just seems like an inhumane way to put an animal down.

It actually seems out of character for Dwight to do this. He loves Angela and that is seen throughout the show up to that point by him doing various tasks and deeds for her. Even quitting for her in order to continue to hide their relationship.

But the way he went about putting the cat down by freezing it while it is still alive and not expecting Angela to realize that he is the one who killed it seems illogical to me. Dwight surely would've realized Angela would've found out, and he should've put the cat down in a more humane way to make it look like the cat's sickness finally killed it.

I just feel like it doesn't fit Dwight's character and makes him seem much more of a sociopath. To me it is much more horrific than it is comical. So the character motivation is puzzling to me. Any insight to why Dwight went through with killing the cat in this manner would be fantastic.