My gut tells me it's going to be a contextual response. There will be personal aspects, things we've thought of, things we've been trained for, things we've planned in the safety of our imaginations but, when the stuff hits the fan, then I think something else takes over. Something about that moment in time, whatever was going through your mind, whatever you perceive to be the issues at the moment, you react. You don''t think; you don't weigh alternatives, you don't calculate conseqences; you react.
Personal reflections by a good many decorated soldiers, fire fighters, and policemen indicates that they did what they did because it was the only thing they could do. Yes, they had been trained but so had all the other soldiers, fire fighters and policemen in the immediate vicinity but they were the ones who reacted.
Given different contexts, my bet is that everyone present would react differently.