An unlucky fishery worker took a spill down the main walkway, either as a result of bullying from the militia (resulting in Dunn Sterusfikod, the unfortunate dorf in question,) being knocked off the ramps or simply trying to avoid sharing a tile with another unit. Regardless, Dunn's been killed by falling a fair distance onto the execution spikes, his head being spit and the remains pushed into his shortly after thoroughly mangled torso.
As I don't wanna risk crashes checking who knew him, I'll just wait for the unhappy dorfs to tell me.
EDIT: It seems that mining out some mineral veins are to blame for all these deaths, as they provide a place to stand along the route up and down the fort. There's also been accounts of illicit climbing around the main shaft, and three dwarves now (a wood burner named Kris, a soldier dubbed Dosh, and Dunn the fishery worker from before,) have all died in climbing mishaps that ended with them plummeting some 7+ levels to thier deaths. As none of them were particularly valuable it's no skin off my bones, but to protect the actual competent workers and soldiers, a silver retracting bridge is being installed to prevent anything worse than the odd busted bone.
I thought Dunn was a fluke until I saw an announcement for Dosh being found dead and Kris exploding into giblets in the same vicinity while I was checking on Ash and our adamantine reserves. And I laughed hysterically the whole while. Man, it feels good not caring about their deaths now that decent soldiers are semi-expendable.
And on the plus side, the combination of drop and wooden stakes = death to metal coated dwarves, so i know it'll work like a charm on elven POWs!