So, I'm putting up a big 55-tile wide, round mold for casting a tower of obsidian 28 Z-levels tall (goes all the way underground as well). I just recently learned of the FILO order of operations which was saving me time on walls, as well as building shorter scaffolds to speed up the straight portions of the circle.
Upon pulling my first row of scaffolds down, I learned that the FILO operations don't work so well with things when you take them down, and a weaponsmith paid the price for my ignorance (!!?). He might get better in a few years. I became more careful...
Early the following season I was another Z-Level up on the mold and was carefully pulling down floor grates one at a time and all of a sudden Urist McKittenButcher has suffocated to death. What?!@ He wasn't sparring, he wasn't outdoors. How did he suffocate? Did he finally choke on those dromedary cheese milkshakes he loved so much?
I was mystified, searched for several minutes but couldn't find the body anywhere, and went on with my day.
Several grates later Urist the Planter has died due to a sudden stop. What?! Had someone decided to take their own life by jumping from the top of the tower? Again, no body... Just one fewer mouth to feed. I was wondering if my site was built upon an old Olmann burial ground.
Mere moments later, I drop another grate and realize that not only were the grates falling from their suspended spot, but they were killing the dwarves who were walking into the center of the mold (currently purposed as a drink area, statue garden, and training area) as they passed underneath the grates.
Now, I regret my carelessness didn't take the life of a noble instead, but I learned some valuable information, and subsequently put some grates up lower down to catch the falling objects before they eradicate anyone else useful.
Now to dream up some inordinately, pointlessly, ridiculous contrivance for dropping grates onto the heads of invaders on command so that I can start exporting Urist McMallahan's Homemade Goblin Fries, extruded right here at home!