I had, a while ago, decided to wall in a human caravan, in an effort to get their stuff when they died. It was a good plan, so of course I had to screw it up. After the few days of playing, I decided that they weren't dying fast enough. Drowning them in the room wasn't an available option, as I'd have no way of draining the room.
Then, the idea hit me...why not collapse the roof on them?
(if you're not facepalming now, you should)
So I went to the level and spot above the depot, mined out a room, selected a chunk of the floor to drop (a nice 5x5 square sound nice?), channeled around that, and dropped it.
(now, up to this point, this seemed like a great idea)
The ceiling crashed down on the trade depot, killing everyone in it...or so I thought. Part of the ceiling crashed through the floor into a ore storage room, dumping 2 humans (one merchant and a crossbowman) and 2 horses into it. a dwarf or two were knocked unconsious, as well as the humans and horses.
then all hell broke loose.
the horses woke up, and went insane. they ganked the humans, then went after my dwarves. one was killed outright, and the rest ran screaming around the room (one of them recently given birth and carrying a baby). I decided to activate the clerk/axedwarf, and send him in to kill the horses before they killed anyone else. it makes perfect sense that the clerk was asleep when i activated him.
sigh
so having to wait until he woke up, I activated another dwarf in the room (convieniently one being chased) and told him to turn and attack. CURBSTOMPED BY HORSE. the clerk/axedwarf finally woke up, and attacked one of the horses (killed it), but not before that horse killed another dwarf. the clerk/axedwarf chased down and killed the last horse chasing the new mother and baby.
I couldn't reload, as I hadn't saved for at least 2 hrs and had done a lot of work.
all in all:
3 or 4 humans dead
3 horses dead
3 dwarves dead
*facepalms*