it sounds you already have an idea of your answer.
I'd agree with Frank - probably depends on the situation. Although I've been in a few conflicts, there is only once I think someone would have actually killed me.
What I learnt is that i. training is necessary to respond ii. your training/sub-concious takes over iii. it is the little things that keep you alive (such as body movement and awareness), not techniques.
i.e. it's no point thinking you could think in such a situation - you just have to hope you've trained your body to move.