My mind has this sort of off switch. I can overcome just about anything if I choose to, however, the challenge isn't what I would do in the heat of the moment, but how I would recover afterward. If I was put in a life or death situation I believe pretty readily that I would be willing to kill with my bare hands if need be, and chances are good that if the threat were imminent and largely inescapable, I'd probably disregard survival and focus on killing the threat at all costs. This probably defeats the purpose, but that's just how I am.
I've been on the business end of a gun, I've faced trigger-happy nitwits that think shooting an unarmed man is somehow justified (I've never fired a gun and refuse to carry... I actually loathe violence), and every time I've been in this kind of danger I've been able to talk my way out. Macho pride means nothing when you're staring into the barrel of a gun, so yielding to the guy with the gun isn't my idea of losing or surrendering, since the assholes never shoot and I'm still here, I'd think that meant I got what I wanted and, in the end, I won.
I will offer this, to anyone that thinks the decision is a fast and easy one to make; the consequences of having another person's blood on your hands, whatever the reason, can be a lot harder than getting their blood on your hands to begin with.
