I have watched some police training. They do shoot at 50 yds. the high score ring might be about 6 in wide by 10 in high.
Bullseye 50-yard 8 ring (the black) is 8-9 inches diameter. Those good shooters can keep their shots in there, slow fire.
25-yard black is 5-6 inches, 5 shots in 20 or 10 seconds.
Good shooters can keep them in the black.
What he did was skillful, but possible with practice.
But the paper versus person stress factor could be hard. If he knew he was practiced, and then just went on his training, I can see it.
I credit his grandfather.
Drilling him so that it came to him automatically under fire. You would expect this of a military man. Not some young kid working at the local pizza store - which is what is listed on his facebook page.
I expect his grandfather had some kind of training.
Had the shooter not stayed in the bathroom for an hour it would have been mass murder because Hero might not have been there.