I'm going to go get lunch, but the most important question I think the PA asked TM was when she asked him what he had to do to ready the shotgun to kill someone. He said remove the safety and flip back some other thing. I don't remember what that thing is, but it seems like he had to do two things.
I don't think he could have done both things in the seconds that transpired in front of the truck. He had to already have done it before AA came around the side of that truck, and that is NOT consistent with shooting AA to keep him from taking the gun.
I'll further say that if he hadn't taken those two steps, then AA -- if he got the gun -- would have to figure out that he needed to perform those two steps. How do we even know AA knew how to operate a shotgun? I can say I don't know how to. I don't know how to remove a safety and whatever else was said.
The bottom line is TM came out there with a loaded shotgun to ask questions. And I believe he had that shotgun ready to go, safety off and everything when he raised it up at AA because -- just like TM was trained -- you don't raise a gun at someone unless you're ready to shot it.