I get the annual goblin siege a little early this year (late fall). Everyone's already inside and the goblins take losses and retreat.
Then I decide: "Cancle the burrow orders and let's go outside to gather goblinite. Chop trees and build roads too. And let's get some of the stuff from those merchants who died in the ambush a couple years back. We have a whole year till they show up again."
Guess what happens 2 months later?
Vile force of darkness!! And quite a few dwarves are happily working and hauling things outside, cut off by goblins. Mini face-palm
So after I get everyone possible inside and raise the bridge I get this great idea to dig an emergency entrance tunnel to the other side of the map and make it part of the burrow. A few lucky ones will be able to make it inside still.
No. Everyone outside is chased down and dies. So then I go back to focus on killing the invaders, etc. Start noticing that we are striking gems and minerals, but write it off to some bedroom expansions I must have been in the middle of. Get done killing a batch of trolls in the courtyard, but notice that some dogs and a weaver just died?! Who can guess facepalm #2?
Lazy miners finally dug that emergency tunnel
Now I have goblins inside threatening the beedrooms and magma forges.
Send some squads to deal with it, a little messy but could have been worse. Look over and see how to seal things up again, and a dozen pikegoblins with swordmaster are comming. Send military into the breach to defend while we build some doors. Kill them without any serious injuries, then I see a dozen lashers comming with a dozen archers. I try to retreat but 4 archers and my macelord want to stick it out. I feed a squad in there to try to back up the macelord, and the meat grinder starts turning. This thing turns into a total BLOODBATH. War dogs and dwarves start dieing, macelord gets snipered. Spearmaster buys the farm. I'm like "that's it". Activate all of the other squads and even the noobies with wooden weapons in the militia. Everyone goes in, and the job gets done.
Butcher's bill:2 legendary fighters
3 militia captains (all skilled fighters with some leadership levels)
20 other military
random civilians who got scared into the tunnel or decided to start hauling corpses during the fight
? war/hunting dogs
Tunnel has been sealed, nobody is allowed outside for a while until I'm ready for more fun.
Future emergency tunnels will be designed with curves and a building-destroyer-proof way to close