What even happened?

Hang-fire, bad primer most likely. This is why you CLEAR malfunctions immediately.

How will you answer?

Hangfire. Delayed ignition, could be a bad primer or propellant. I had some Indian made 303 British that would do that. Pulled a few projectiles and found some were contaminated with what looked like floor sweepings and dryer lint. Scary stuff.

hang fire, that's why if it happens you should leave it pointed downrange before messing with it any further for a few minutes.

At least he didn't look down the barrel to see what was going on. 😳

Honestly I don't know what happened but I would have checked and cleared the chamber each time. I prefer to keep my fingers, thumbs, hands, nose, eyes and face I sincerely hope this man kept his but I have seen some ugly pictures, nope no, safety first every time!

It would be a hang fire if it wasn't staged. The bottle explodes. It's not the rifle firing. Watch it at 0.25x speed. This isn't the only dodgy frame in the video.

Looks more like hang fire + out of battery detonation. That bolt looked janky.

Is that tannerite? If you slow the video, the container goes, not the gun.

Hangfire. Should have either waited longer pointed down the range, or ejected the bullet. Looks like it fired after he set it t on the table.

Staged ... 100% fake. As you can see here, the gun does not move, but the bag in front explodes even though the firearm is not pointed towards it.