During the last beast attack, 40 good military dwarves were brutally murdered by a bronze colossus because the a lever was pulled too late. The Bronze colossus is now safely trapped in a cage and could serve as an immortal target for Marksdwarves in the future. There are 56 survivors in the fortress, among them are two expert crossbowmen, 7 dabbling crossbowmen, and 20 dabbling melee fighters, mostly macedwarves.
I was working on a magma trap which would crush future sieges, I dug a staircase into the magma-forging heart of the fortress and I left it completely unprotected, opened for everyone to use. Now the magma trap is nowhere near done, fortress is opened and we have two marskdwarves and 27 recruits facing a siege (first squad, mostly melee invaders, entered the map). This is the second siege, so I don't expect anything too big.
What do should I do? I figure I have three or four options.
1. Savescum. DFHack die, revert to last savegame, cover up the staircase into the fortress. Face the siege again and turtle up.
2. Draft everyone in the military (56 dwarves), let them put leather armor on, grab some weapons and fight. If it is only one or two dozens Goblins, we might even win, although the our losses would be great.
3. Try to quickly build two floor tiles over the staricase (2x1) before the goblins come, maybe send our livestock as bait, then try to hide. If we fail to construct the two floor tiles in time, we'd fight, although many of our dwarves will not have any armor on.
4. Release the Bronze colossus, let him fight the goblins, and try to trap him again afterwards.