I'm testing a system that will not only make sieges/ambushes/thieves a joke but also will make sure that if they get in my fort they won't be leaving...
There are two issues mainly:
1) After you kill/injure/cage some percentage of enemies in a siege the remaining will turn back and run away...
2) Ambushers once revealed turn back and run away...
as I said I want every last creature in the siege/ambush to not leave...
The only way I think this is possible is to let them come into your fort via the long hallway route, but instead of triggering traps that injure/kill them, dropping them 1 z-level down into a containment chamber, after the last sieger enters and falls you can mass kill them...
The problem are ambushers like kobolds, they don't trigger traps, so they step right on the pressure plate that leads to my retractable bridge drop hallway and they won't drop themselves, so I'm testing this:
In the middle of the dropping hallway I have a dog looking down through a floor grate on a pasture zone, when the kobold gets to the middle of the bridge they get spotted as expected...
what I was also expecting was the same behaviour that happens when an enemy approaches a pastured animal: they leave the pasture and run away... because of that behind the floor grate I placed a pressure plate, thinking that the dog I pastured would spot the kobold ambushing bellow through the floor grate, and then would run away from the pasture, step on the plate and retract the bridge bellow the kobold and drop it into the containment chamber... but noooo, the dog stays put on the pasture zone...
Maybe it's because the dog wants to attack the kobold instead of running away? I'll try with a pig then... maybe it's because the animal can't path out of the 2x1 room? (the room has a floor grate where the pasture is and the pressure plate, and it's closed by a pet un-passable door..