He had to have that gun in his hand and ready to fire. From the witnesses I heard, there was an exchange of words. I would say that Reeves helped to escalate matters, and he didn’t recoil in fear for his own life, he leaned forward and stuck his arm straight out when he shot Oulson. I’ll send you the YouTube link to that Air Force Corporal’s testimony. I know you have seen it, but might want to bookmark it for further discussion.
If true, that also would seem to establish the likelihood the shooter after leaving his seat to complain to management about the victim, readied his weapon for easy access for round 2, and returned to his seat.