The plaintiff didn't buttfire the rocket. He fell off the deck purportedly because he was startled and there was no railing.
[Defendant] placed a bottle rocket in his anus [and] ignited the fuse, but instead of launching, the bottle rocket blew up in Defendant's rectum, and this startled plaintiff and caused him to jump back, at which time he fell off of the ATO deck
I think he probably fell because he was laughing so hard.
That said, it's still a sad commentary on our times and the litigious nature of our society.

∆∆