Being one of the few people who migrated from adventure mode to dwarf mode with .17 instead of the other way around, I've started off my new fort making some newbie mistakes.
I was trying to make an area exposed to the open air by my butcher, so if stuff rotted before dwarves could get to it, I could at least save it from producing miasma, however, an error while channelling caused my second-best miner to fall through, smashing through the dug out area below, going straight through in to the sleeping quarters two levels below, landing on some poor sleeping dwarf and crushing him. The miner broke all of his limbs and horribly bruised both his upper and lower body, while the sleeping dwarf got away with fewer bruises and no broken bones (His bedroom is covered in blood, though). The miner is probably done for, as my medical team currently consist of a novice diagnostician and a novice bone doctor, but hey, Fun.
Edit: Scratch that, the miner, who I now figure out is actually my best and only legendary miner, got up, promptly healed every bruise he had, and got to work detailing the stone in the dining room. His arms and legs are broken, but he isn't bothered by it. Despite his attribute for handling pain being below average. I will have to reward this dwarf suitably.