"I've noticed something about people who employ violence in a planned fashion like this. I'm talking about people who do not have a history, experience, in it. not applying to people who are experienced in it, who have grown up in it, to which violence is a first or early response.

It seems that if they don't have a history of carrying out violence the plan in their head, their preconceived course of events, is a fragile thing. Much like the inexperienced commanding officer with a battle plan in his head, who cannot adapt when those plans must change. So they fall apart in confusion, not knowing what to do.

How that applies to this thread, I don't know. It is just an observation that comes to mind."

This applies in just the manner that I have been saying. These mass shooters are not badass Russian Special Forces types who have been in combat many times, and who have killed and been shot at before. These are Keyboard Commandos whose experience is video games.
So they are going to be much more vulnerable than an experienced combat veteran, and when met with armed opposition they are likely to just give up, or else, to go ahead and kill themselves.