The reason you shoot a person is to make them stop doing what they are doing. Put another way, you shoot an attacker to cause him or her to stop the life-threatening attack. A firearm is a tool of deadly force, your intent when using it against a violent criminal is not to kill, but simply to stop the attack. You are not a killer. This is accomplished by shooting at the criminal until he or she no longer presents a deadly threat. You cannot assume the attack is over simply because your shots have hit the attacker, even in a vital area. Criminals high on drugs or possessing an extreme will to live can continue their violent attack even after sustaining lethal wounds to vital areas. You cannot assume incapacitation just because the attacker has fallen, they still may have a chance to deliver deadly force. Once the attacker is no longer a deadly threat, and they have truly stopped, either by surrendering, fleeing, or are lying down. You are no longer legally or ethically justified in using deadly force on that person. In other words, you cannot keep shooting them. That then becomes murder by you. Quite often after shooting your attacker you may not have incapacitated them. They may stop the attack because they just do not want to be shot anymore and give up.