or not
The timeline here will be interesting --
How long does it take for a retired cop who hasn't pulled his gun in years to pull his weapon, aim and fire???
The patrons describe the popcorn flying almost instantaneous with the gunshot meaning that he may have had the gun out and pointed at the victim before the popcorn flew.
The popcorn may have been a defensive move when the old guy pulled his gun.
I have not read that but that is a possibility. Just speculating on what the arguments could be, not endorsing them.