[higgmeister]

Their is no reason to killed someone, when you can simply aim your gun at the perp and blow his balls off.

That is not what police officers are commissioned to do. If deadly force is warranted it must be to kill or not used at all. That is also the first rule of survival.

[Mark17]

If deadly force is warranted it must be to kill or not used at all.

I believe the term is, "shoot to stop the threat." If the first shot hits the dude between the eyes, I would say the threat would be stopped, and to stop shooting. It just depends how many rounds it takes to stop the threat.