These questions are why I took up aikido instead of continuing with jiujitsu and kung fu.

Rather than letting someone kill (or injure, or whatever) me or someone else, the preferable solution for all concerned is to prevent them from doing so without harm, and leading them to stop trying to inflict harm. Backing up this lofty ambition is the hard part, and that's where the years and decades of practice come in. It's the best answer I've found so far.