I just do what seems right. If the situation requires a split second decision and I have time to instinctively see one alternative that's good or better than the rest, it'll be my choice proportionaly as quick as it's better than everything else.. If the situation is too quick, I'll probably freeze just a bit too long like every other normal person.
I admit my answer if funny, but it's a funny question too. We don't get any details that could change the answer from flat out yes to flat out no, fight or flight
That sort of situation is something that's important enough that at some point you can't help but realize you have to think about it today, so that you can be better prepared if it ever happened. There's lots of ways to get ready (obviously it's always just a plan, and 'no plan survives the first moments of the actual event'), I guess you could call it conditioning yourself. There's a passive side to it, like learning to read someone's footwork and body language in a fight, to help you recognize their intentions... And there's an active side to it, like sharpening your reflexes, being in good shape, etc. That's just an analogy.
I think situations of danger are no different from any other situation. What you do is what you're going to live with. Being lucid and doing your best whatever the outcome might be, or however bad things might seem, is what matters. Regret is useless. What matters is the present.
I could go on but that's it basicaly.