Whoa, completely 4got I made this topic. I think I'll try leaving a monk with the ghost since I have horrible luck and no patients for things that require good luck (spawn locations). Thanks.
If you warp everyone out, you can still get mission by going to the east, getting some sacrabs and warping back, best to keep someone inside, just so you can force spawn them. (just left to the gate at you are entering normal way).
The necrotic traversal trick doesn't work anymore, the scarabs don't spawn close enough. And of course I'm going for it w/o regards to completing the mission but we can't leave him alone for long enough to kill the generals. The wurms destroy him.
Just did it. Hope for a fleshy boss to spawn at near the gate, and rape them. I'd say there's a 3/5 chance of getting a good spawn.
Also, I have found that letting your character die while fighting the other bosses seems to teleport your heroes/henchmen to the bridge (past the gate), if you play around with the flagging. I didn't find this method myself, of course... Saw it on the GW Wiki discussion page for this mish.