Watched it a few times. The guy was standing in the top left corner next to what looked like an usher asking a question. The usher points at the guy sitting and the weapon comes up. Going to guess at a pistol gripped shotty or a sawed off rifle. Guy who stood was reaching for something and if I had to guess a concealed weapon in his back right by pocket inside his waistband but couldn't draw fast enough to do any good.
When he stood up the people in the foyer took notice and was watching also trying to draw but hesitated before drawing and firing on the shooter.
I am going to make a guess that this was contracted like a hit or something. The usher pointing the guy out makes me guess that the name of the person was asked to verify and at that point the bad guy aimed and fired. I could be wrong but would not be surprised if that is the case.
Shows me all the more that you have to practice the draw. If you can't bring it to bear you may as well have brought a rubber duck to the gunfight.
One report that I read or saw (can't remember which right now) stated that the initial "good guy with a gun" was an armed security person. Now, whether that person was an off-duty police officer or just a church-goer that was armed, I don't know.
In our church, there are some that are armed, and there is usually at least one person in the lobby/foyer that is armed but concealed. I've even been one of those in the past.
And, I used the word "church-goer" for a reason. So far as I know, the term "parishioner" is primarily for Catholic or perhaps Episcopalian churches. I am a member of a church of Christ, and we never use the word "parishioner."
Looked to me like a headshot from the responding churchgoer... if you look close, it almost looks to me like the top of the guy's head came off or he was wearing a hood or mask or something. I dunno, that's just what it looked like.
Looked to me all of the LEO's in that interview video were pi$$ed as hell they didn't get to put a few in the guy. I guess they'll have to wait until he's interred.