Interesting conversation. COM is my goal if I am ever in this situation. I hope that this will stop the threat, yet understand that it may not. Being prepared for whatever happens next, whether that is running, hiding, fighting, or all three will determine the outcome. Having the training and ability to assess and act accordingly is a serious responsibility that cannot be taken too seriously IMO.
I do not know about shots other than center mass if that shot can be taken. I feel it I ever had to pull a gun, I am going to try to terminate the threat for good.
Survival is the only goal in this situation. Stopping the threat "for good" is excellent internet machismo, but bad policy.