I think it is human nature to look over any such situation and consider what might possibly have been done differently that may have changed the outcome or saved a life. Maybe it is "fantasy", but I would hope that anyone would recognize and take full advantage of any brief opportunity to end it prematurely, should one be presented. It is a given that we should protect ourselves and our families, and stay out of the way of law enforcement, and not cause further chaos, but I would hope that in such a situation, should an opportunity present itself that I could do something to save another or a stranger, that I would not fail to act, but flee instead of facing the potential danger.