AT, we talked about an hour, and I can tell you this...he was thinking, making decisions, and stayed aware from the time he pulled into the parking lot.
Here are a few more details.
It was a diesel truck, and he noticed the engine was running when he parked. Of course, many times people leave them running because they're diesels.
When he came out of the store he noticed it was still idling and took note.
But with one foot on the ground and one inside his Jeep Cherokee, the perp jumped from the passenger side door and threw down on him in a heartbeat.
Instinctively, he reached up and calmly kept pushing the barrel aside since it was right in his face.
He also said, "Man, don't do this. This is a bad decision your making here." Or something to that effect.
That's when he weighed the reality of the situation and asked himself, "Am I in a draw and shoot scene here? Should I really draw my gun and fire?"
He quickly decided it was because he saw it in the eyes of the perp. The guy meant business and began to look even harder and more intentional. And his voice became harder and more amped.
Pretending to reach for his wallet, he was thinking about the location of the external safety on his pistol which he carried IWB in a kidney position, right above his wallet.
He found it, took it off safety and, in one motion, swept across his lap and fired while keeping the shotgun barrel pushed away.
The perp fell/jumped/move backwards between the vehicles and rolled behind the tailgate.
By the time my friend exited the car and carefully moved behind the truck, ready to fire again if necessary, the perp had dropped the shotgun and was pulling up his pants to run into the darkness.
My friend was on with 911 and made sure they guy didn't reappear to attack again.
It was pretty dadgum textbook and his level head and training just flat worked.