Just had another one last night.
I'm building a new living area 1 z-level above the ground, supported by the walls defending the access stairs. Obviously, it extends horizontally far beyond said walls.
Well, I made some minor mistakes constructing a couple areas, and marked the first batch for deconstruction. The slave labor hard-working children did their jobs well, causing the blocks making up the mistakes to fall to the ground below. When I went down a z-level to forbid them (it's a ridiculously long walk from one side of the support-wall to the other thanks to a limited-access roadway), I saw a stunned dog right on the tile where a block had fallen. The poor thing had had a big ol' chunk of rock dropped on his head. Luckily, it was only one item and 1 z-level, so he had a few minor nicks and a couple brown injuries.
After setting up the replacement construction in the first area, I went to the next batch, which was about a screen and a half to the east. As before, the workers did their jobs, blocks were dropping out of the way...and I get a message that "Stray Dog (tame) has been killed by a collision with an object". I went and looked under the work site and it was the same dog.
The poor thing, easily a thousand-tile walk from my front gates, had not just had a giant rock dropped on him, but then, when he tried to go back home, he had had ANOTHER dropped on him.