Let's remember that the mindset is neither shoot-to-kill nor shoot-to-wound. It is shoot-to-stop.
The reality is that effectively stopping an assailant who has manifest the intent and ability to cause you death or great bodily injury will most likely require that you use a degree of force likely to cause death or great bodily injury. But that is not the same thing as intending to kill.
While your intent is to stop and not kill, the reality is that using force effectively to stop an assailant may very well cause his death. One needs to be able to accept that might be the result of his efforts to protect himself.
"It is long been a principle of ours that one is no more armed because he has possession of a firearm than he is a musician because he owns a piano. There is no point in having a gun if you are not capable of using it skillfully." -- Jeff Cooper