In my case it was this one lunatic that decided to fuck the mission and come home early as part of a migrant wave. His commander never came home.
I ended up abandoning that world just because i needed to test newer features in my mod. I decided to found a new fort, on top of a volcano, for that. But i got distracted building a huge 7 tile wide two story deep trench around the entire fort, all the walls of which i have smoothed over or built from blocks. The dwarves dont even have bedrooms or a dining hall yet, theyve been napping in empty dorm beds in the few available hallways (miners have been busy trenching and smoothing walls) and eating off the lids of barrels, chugging booze out of the barrel like their uncivilized ancestors did before mugs worked (craftsdwarves on masonry duty building blocks and walls around the citadel). But this fortress is literally impregnable to anything that cant fly.
The trench is now full to the brim with magma and includes two retracting bridges for dumping that magma into the trade depot tunnel below. Havent dug the drains to get it out of the tunnel yet. I want to build steel and glass traps for magma proofing in the tunnel to catch or kill invaders. I have sand, i dont yet know if i have iron, but i think i had flux, and obviously magma.