Well my military's been training for 10 years. I have 2 axelords left, 5 swordmasters, 7 hammerdwarves, 7 elite marksdwaves and 2 mace lords, all decked out in blue metal. Time to clean up my caverns - there's about 10 FBs down there.
So I start with cavern 3: 4 FBs, no casualties except those stupid peasants who rushed to pick stone and died to one of the FBs with deadly blood - guess I had forgotten to remove the stone stockpile near my catapult training area.
I let my military rest up for a month, then I go to cavern 2 and I keep my macedwarves out of the fight "just in case". I open up the cavern, station my 21 dwarves inside and build a wall to seal the cavern up "just in case". Queue in Soshosh, a not so though insectoid FB with Deadly Dust (and another FB made out of vomit - my military actually ended up killing 2 FBs at the same time). My military easily dispatches both FBs with no casualties so I proceed to unseal the cavern. While the wall is being deconstructed, I inspect my military and notice something's wrong. Very. Very. Very. Very. Very wrong.
But hey, the cavern I fought in is used as a water source for my hospital - in other words the hospital is about 40 squares away from my military with plenty of beds, soap, a dedicated medical staff, 20 wells, a ramp with water at the entrance to wash off dwarves coming in and a another ramp in front of my row of wells so that dwarves that give water clean themselves automatically. In other words: I got good hospital going. So I tell myself, I'll just let my rotting military out and try to save them, I mean, what's the worst that could happen?.
About 5 of my dwarves made it to the hospital being passing out - including the Axelord Nish. The rest started rotting and emitting miasma on the way to the hospital - in the middle of my main stairway. If you've ever had this happen to you, you know exactly what happened next. The rot spreads to the entire fortress. My medical team can't keep up and gets infected. I can't see anything in my hospital because the few military dwarves that get carried there (recovering the wounded made most of my civilians become infected) are emitting too much miasma. I know exactly what's going to happen to my population so I start the damage control:
1) I mass produce coffins and caskets.
2) I use the 7 miners I was grooming for my military (legendary miners/engravers/pump operators, working on wood cutting and siege operating) and decide to flood all of the levels below my hospital and build a pump stack to the surface to flood my entire fortress
3) I move my food and booze supplies to safe areas above ground just in case I can't contain the rot
As I'm doing all this, my fort is caught in the middle of a tantrum spiral and everybody's doing left and right. So to make my day worse, another FB shows up. One of my reserve Mace Dwarves had actually managed to get himself infected. Nish the Axelord was actually able to survive the rot (although every single part of his body/skin is showing up as brown or yellow). So I send all of my squads to go duke it out below my hospital against a FB with deadly blood. After a while, I see a hammerdwarf showing up to the fight: I'm confused since all of my hammer dwarves are very, very dead. So I look at who it is and realize that it's my Legendary Leatherworker.
Going back in time to talk about this guy - his name's Solon and he was my fort's Leatherworker. During an early ambush, he got himself caught by a goblin or a troll and back then I saw that his spine was shattered and he had several other major wounds to his arms and legs. I assumed he was as good as dead. A few months after that ambush I had my Hospital set and running and decided to find the dwarf with the best recuperative stat and make him sustain injuries with a danger room fitted with glass spikes. As I'm inspecting my dwarves, I come across Solon who is "Incredibly quick to heal". Off to the military you go, useless dwarf. So I station him to the danger room and wait. And wait. And wait. Then I go look at him since he's not showing up to his post and see that he's very slowly making his way to my danger room. I inspect him and see that his spine is shattered, making my realize that he was the Leatherworker I had written off as being dead a few months ago.
So back to the fight with the FB under my hospital: Solon shows up after my Axelord and Macelord have been going at it for a while. I laugh for a good minute, the FB dies and things go back to "normal".
A year later - I'm trying to figure out how actually make water wheels work, I have 37 out of 170 dwarves still alive, my Queen has been extremely helpful by feeding, watering and cleaning patients for the past year, a goblin siege was stopped dead in its tracks by a very angry Nish (and a few dozen cage traps). The bottom half of my fort has had its corridors cleaned up by a slow and steady trickle of water. Four of my 7 miners are still alive - one of which is constantly throwing tantrums. I'm running out of booze and my brewer and planter died. I have food to feed a thousand dwarves for the next century. And my crippled Leatherwork is now decked out in blue metal and once things have finally stabilized, he'll start training against goblins. I'll make him my new Militia Commander. Because god damn, he crawled through an entire fortress filled with miasma, rotting limbs and animals, pus and blood to fight a forgotten beast along side two legendary warriors.
A true dwarf.