*pries the bunny off with a stick*

Need a bit of input, gang. I have most of the opening two scenes of a crossover fic--a sequel of sorts to "There and Back Again"--but I'm not having much success figuring out the mission involved. Here's where things stand (slight spoilers for the second show's fifth season):

( It's Fall 1944, and as the Heroes head into the emergency tunnel... )

It's probably a case of taking out a heavily-defended factory/refinery/ammo dump/radar installation/lab, but I could use some suggestions....
And yes, I will be a good girl and not try to finish this until I get my current dissertation chapters turned in.