Dear NOYB,
I hear your points. It is still unclear to me why the gun would him. If the idea is to get out alive, then not going at all would be a better choice. Or go unarmed or lightly armed and keep a low profile.
My understanding was that he was running away. This is a point with gun engagement which is different than your typical crawl. You have to commit to use the gun or call it off. Everything else is very risky. In other words, shoot the attacker fatally or not, or get rid of the gun or hold it by the muzzle. One can try to calmly back away with a drawn gun. But do not make a break for it.
I understand that he knew how to shoot. I doubt he enough to detail.