Keep in mind also the knock out guns are virtually silent. Using them avoids a lot of issues with noise, muzzle flash etc.

It was definitely to knock them out, not kill them.
If you remember the scene when Simon is talking to the bank manager - when he gets a shot in the neck, there's someone behind him to catch him when he falls, so as not to hurt him. They wouldn't have cared if he fell had he received a lethal injection.

I'm not sure what you mean.
I want the doctor to take your picture so I can look at you from inside as well.

You mean like Isis?

I disagree. It is one thing to kill adults. It is entirely different to kill children. That's not hypocritical - that's just not being a monster, like he said.
I want the doctor to take your picture so I can look at you from inside as well.

The monster line was to convey that he wouldn't blow up a building full of children, not that he wouldn't kill innocent people. The gun thing was mostly likely to keep from drawing unnecessary attention to their operation.

My thoughts are that since they were a bank and wanted to get in quickly and no fuss, Simon used tranqs otherwise bullets would have used that nasty habit of spurting blood everywhere. All that mess when they are trying to be covert.
Fav comic book films ever:
Captain America: Winter Solider
Batman Begins
Iron Man
Blade

Why would they care if they killed someone?
Simon is either massively hypocritical, or the film's writer was smoking something.
SPOILERS
SPOILERS
SPOILERS
SPOILERS
I mean, on the subject of (not) blowing up the school his reply was "I'm a soldier, not a monster". Indicating he had no intention of killing anyone.
Yet he blew up a department store in the morning with people on the street.
Also, blowing up the train. OK the film confirms no one was seriously hurtbut there was no way Simon could guarantee that factespecially as McClane was never meant to make it there on timeas McClane himself brings up in the film.
And so, God came forth and proclaimed widescreen is the best.
Sony 16:9

Thanks for your reply.
Why would they care if they killed someone? They killed everyone else.
Honey Badger don't give a 5hit.

I suppose a tranquilizer, otherwise they would use the guns