ok, so let me get your reasoning here.
I see someone pointing a weapon at me, so I automatically assume that during the next second, the person will discharge the weapon? More effective techniques exist for dealing with a situation like this. If we were being held hostage, then I would see what the likelihood of survival of all parties was. Otherwise, what would happen?
You see a gun, and dive in front of the person to "save" him/her and the assailant would just see you fall down and start laughing? I don't see how this could actually happen in real life. And random abstractions serving no apparent purpose are avoided by myself.