Well I also think that a shot to the leg, shoulder or anywhere else that is technically not considered fatal, what if it doesn't have the desired effect? What if they're armed? You take a pot shot at their arm and they don't stop- now they injured, angry, and probably going to present an even greater threat... Like said in Bad Boys II:
Mike Lowery: Look, I'm down with your spiritual enlightenment and all that, but I need to know right now some crackhead come rollin' up behind me with a nine you gonna cook that fool.
Marcus Burnett: Of course, shoot him in the leg.
Mike Lowery: Forget that leg shit, man.
Marcus Burnett: Everybody deserves a little dignity.
Mike Lowery: What about my dignity? Your crackhead gonna be missin' a kneecap, I'm gonna be in a body bag.

