So I decided to be !!economical!! and almost killed two of my legendary axedwarves!
I had a loafer sitting in my hospital for the last ten years with a scarred foot. I decided to knock some sense into him by collapsing the bed he was wasting down a level, so I channeled out the area around him, built a support a level down and attached it to the same lever I was using to power my Danger Room.
Well, apparently that causes an interesting bug! The tile collapsed fine, he woke up, stood there for a sec, then fell right back over and had to be carried to another damn bed. (damn it.) Oddly enough, as I was walling the dolt in so he could starve instead, I noticed several of my legendary axedwarves hobbling in with severe arm wounds. I checked my combat screen and low and behold!
Apparently the training spears actually did some serious damage striking them in the head and snapping a few arms, AND they got struck by clouds of boiling magma (??) and clouds of sand. All within the span of ONE lever pull.
I'm worried about pulling it again now! The support is gone of course, and the axedorfs will get better, but they had serious bone-through-skin wounds which doesn't even happen to my recruits, let alone adamantine-clad legendary ones from training spears!
Edit: can't post the combat log, apparently it's not a recent announcement anymore.