Anytime you decide to introduce a gun into a situation, it’s a good idea to start pulling the trigger immediately after it’s introduced and the gun is still in YOUR possession.
I never can remember the name of that western movie where the hero shoots the guy from under the suds in the bath tub. And as the bad guy falls, the hero says “You always did talk too much.”
That is my idea of how to handle a self defense situation. Never let the guy know what is about to happen...never ever say a word until no one is there to hear it.