Some glorious almost-fun happened. I engineered a 22 level fall (7 above ground, 15 more below; will build the tower higher soon) for my first hammerer, right through the middle of the central (and only) staircase where everyone can and must watch.
Built a floor with a support on top. An unsupported floor (with grates around it) on top of that and on that floor a lever, connected to the support, ready to drop the whole construction and whoever happens to pull it.
The hammerer pulls the lever, the support gives in, the upper floor with the hammerer falls and punches through the lower floor, just as planned.
Only problem: I didn't know dust from cave-ins would travel down all the way through my staircase, from very top to very bottom. It knocked out 12 dwarves of which 5 fell off the stairs and accompanied the hammerer on his flight.
Mild tantruming occured, killing another 2 before I managed to build a quick anti-tantrum machine: a little waterfall through said staircase. Kills FPS, but makes everyone happy. The start lever for it is in my mayors office. I imagine it to have a sign, saying "in case of emergency, pull the make-everyone-happy lever."
Funnily enough, another 22 migrants arrived later that year, despite the danger. I thought that 8 deaths, including one noble would stop the soapmakers from coming for a while.
One question: is there a cleaner and less deadly (for everybody else) way to drop a noble with himself pulling the lever? I don't like executions, suicide is ok, though
@smjjames: Strange... I just drowned a single elf caravan after they brought me nothing but cloth for two years and the next year they had tons of wood, some booze, a few plants and 4 bins of cloth. Must have been of the more intelligent kind.