Never had anyone point a gun at me, but there’s a very distinct side of me that would believe that my life was in danger so long as that person was still alive and had a gun in their hand. Perhaps because it would be. It wouldn’t ‘turn-off’ the moment they turned to (possibly/likely) leave the store. Shifting from survival mode in a deadly confrontation to “Oh, OK, everything’s alright now; no threat” would take me quite a bit longer than a split second.
And that is a valid defense. I do hope the charge is dropped or dismissed. Is the DA one of those Soros a-holes?