And as far as the shoot to kill vs shoot to disable - just about any CHP/CCW class here in Colorado the instructors will tell you this:
1) Do not take the action of shooting somebody lightly. It's not and it's something you will have to live with the rest of your life.
2) Make sure you are 100% certain you know exactly who/what you are shooting at. The guy who shot his intoxicated 19 year old here about 15 years ago could probably explain that one.
3) If you determine you do have to shoot, you unload the gun and don't stop until you hear a dry fire.
That last suggestion there is not something I'd promote to anyone, regardless of their background. Taking the castle doctrine and self defense laws into account, a self-defense shooting is justified so long as the attacker poses a threat. Once the threat is gone, the legal, and arguably moral, justification for shooting someone goes away as well.
Now with adrenaline high, and nerves on edge, it's easier said than done to know exactly when a threat is neutralized. But keep in mind that cops have routinely gotten into trouble for excessive use of firearms, even when they were dealing with a suspect who was armed and dangerous:
Officer Jason Van Dyke Pleads Not Guilty To Murder In Shooting Of Laquan McDonald « CBS Chicago
A firearm owner has an obligation to know when it is and is not necessary to use his weapon in self-defense. In any high-stress situation, where a defender has no other choice, a firearm should be employed to
neutralize the threat. We can talk about the technicalities of shot placement, center of mass, ect. but regardless of where they are going, those shots are intended to neutralize the target. Once the target is no longer a threat, the shooting needs to stop. "Shot to kill" is not a phrase that a civilian or even a cop should be saying because it gives off the wrong perception.
