A lot of it depends on where enemies move next turn, and if we get a Spotted token or not.
If you both just move N, I can move N and use Assault, firing at the two enemies W, and likely taking them both out. My understanding is a Spotted token only raises an alarm if there is an enemy still alive on the tile, so with both eliminated there will be no alarm if one gets pulled. Alternately, you could try to shoot the guy E, just to clear him out in case we ultimately do go that way.
If the next W enemy reinforcement is not a sledgehammer, the crowbar holds and we can all get to the trapdoor room on the following turn (move W, S, S, and use the +1 to go W. Then, no matter what, enemies will not stumble into us on their turn, and we exit the terrain the next turn.
If it IS a sledgehammer, then those troops enter and move N, while we are safely to the E of them, and we can reevaluate from there what we should do.



2, 3