I'd imagine that this is one of those things where, despite mental preparation...you won't actually know what you'll do or how you'll react until the moment is upon you. I'm extremely aggressive and react quickly to confrontational situations (but never involving a gunfight) & would like to think that I'll utilize any means necessary to take the enemy down...including using my hands & fingers in eye-sockets, etc...
...I think I'm capable of full-bore savage mode (dealing with the emotional consequences afterwards, sort of like Chris Kyle in American Sniper). When I was 19, I literally had to fist-fight my much stronger, alcoholic father for control of the house. I won, I completely broke down afterwards (not mentally, but sobbing & emotionally - and it led to a huge talk & an understanding between us) - but for the next 10 years I was "unbreakable" & took on men (argumentatively, not physically) in private life & business life when I perceived unnecessary bullying of people/employees - and always won because I was willing to throw everything away for the sake of winning. The older I get, the better @ sheer, ice-man bluffing I get - and sort of count on the fact that 90% of the population doesn't enjoy conflict, giving me an upper hand.
So I think I'm equipped (and know that at some point, I'll probably be killed, given certain scenarios) - but we'll see.
The sick part is...thinking about it sort of excites me.