Lucky kid. The flash was coming out of the gap between the cylinder and barrel AND the back of the cylinder. The barrel was plugged, just about certainly. The forensics on that would be interesting.
I've see that happen before. At the range I work at we had a S&W do that. There was no obstruction in the barrel, just metal fatigue. You could see where the barrel was cracking right where the threaded section ended. Wish I had taken a pic but the boss didn't let me. We sent the gun off to S&W and they replaced the barrel, free of charge.
Not funny! I have the same model or at least close to it, the Taurus 607. I see the first round flash, looks normal, the second, something is WRONG! Way too much flame and flash from around the cylinder.... Looks like the cylider was out of time...? The last shot looks as if the bullet hit the barrel, tearing it away from the frame! Saw a Model 19 S&W do that just after the shooter said he was getting hit by shaved lead from the cylinder!
Comment on Youtube: "It's his own fault. He should have pulled the other trigger, not the trigger with the label "Explode barrel" ROFL. Some replies make me laugh some times.
Maybe it's just me but the whole thing stinks of a set up folks . How many times do people go to the range and film their day shooting ? What are the chances of it happening while a person happen to have been filming it ? I would bet the gun was intentinally damaged in some way to make the whole thing happen .