A wounded Clothier/FirstPick threw a tantrum, and on the way to the meeting about it also threw a sand pear. My well-trained Hunter/Markdorf dodged it just fine, right into a Bone Carver/Marksdorf in a bad mood, who took it personally and joined the non-lethal tantrum fight in a semi-lethal fight of his own (bone crossbows do much less damage than punching, so not bad anyway). If the Hunter had fought back he'd have tanned their hides, but he wouldn't, so inevitably he goes down.
I tried to break it up (as the bruising, stunning, and head hits were getting a bit serious) by switching their squads to active/station. That just made them turn nasty, all head shots, but only with their fists (stopped using the crossbow, so more dangerous). So I turned off the squads again and the Clothier left the fight. Yay! Bone Carver kept hitting the Hunter in the head though, now with a Robe for some reason (which really hurt!, must find how to weaponise robes) and when a passing Fisher/Axedorf saw that he joined in and cut the Hunter's head off in one hit. Now there's a baby on the loose and everyone's a bit more stressed. Also, no crime report, so apparently dodging into people puts you on the rebel side sometimes.
Unless my crime system's bugged with that insane dwarf stuck in the jail, I haven't had any reports for a long time, but that was the first tantrum in ages too, and the Baron/Mayor only ever wants doors, so maybe not.
I was just working on cleaning all the exploded cats out of the well (or digging a new shaft, funny what happens when you're distracted) when the game gave me a "1822 segmentation fault", so that all never happened now. 40.24 should save quite so many tantrums from all the wounded dorfs.