One of the comments said it was a LiPo going off another one said they operator tried to fire some sort of pyro.

Whatever it was I'm sure your original assessment was correct; it wasn't a planned event unless the guy was looking to exit the hobby...

I noticed there more than a few observers who thought the guy's misfortune was funny, THAT would have been annoying.

And I worry about fuel fires in my models.

Yep, looking closely at the video sequence looks like a simulated main gun firing that went wrong...




Either that or there was a 1/6 IS-2 off screen somewhere...

Jerry