I read that article, that's really interesting. Of course there is some process of combustion to create the flash, but I had no idea it was capable of severely burning a victim. I guess LE really do take the phrase "non-lethal" to its reasonable limits. You're right, though, IRL situations which may be deemed safe, in their respective circumstances, may become unsafe even in a recreational environment, such as your case.
Ah well, they do say "fools rush in"...