well, just had my most epic battle to date. Quite literally teh smoke is still slowly dissappaiting aroudn the troll corpses.
I've been slowly gathering masses and masses of goblins from sieges and ambushes, and putthing them in the same cage. I think I had a good 50 or so? maybe? I'm not sure. Could be double that, could be half. I set it up so my 3 super-elite sword dwarves, fully equipped in great steal, would be facing the hoard upon release. The gate was raised, the corridor was set I also had 2 trained war dragons behidn a wall in a pen, where they hung out to catch stragglers.
How I assumed it would go : a crapload of goblins and trolls would rush in, my sword dwarves would have a glorious battle slaughtering most of them, sustaining some injuries along the way (possibly death, the odds were against them).
How it actually happened: the dragons escaped and proceeded to breath fire on everything and everyone, vaporising most of the opposition as well as my military. As the goblins ran away and up the tower, the drqagons followed them. My rope-zoo is now missing half the ropes. My goblin-holding area is now without any of my backup goblins or cages. There are fragments of corpses everywhere. i don't even know what I've lost, since many things are not destroyed... but completely vaporized. Also, I learned that dragonfire boils blood and wine, and that boiling troll blood/dwarven wine can burn so hot that it causes dwarves to instantly bleed to death. Also, dragon themselves are vulnerable to attacks, even if their fire destroys all things ever made.