I think this is an AWESOME idea! We could start an AH underground and have more things to spend perks on such as shovels, coffee pots with speakers and a microphone in the Kommandant's office disguised as a picture of Hitler! Perhaps even strudel made by the French POW to bribe the lovable Captain of the guard! The POW's could sneak out through a tree stump (would have to be a new terrain object) and bomb STRAT targets.
I give this the clerick stamp of approval!
cllllleeeeerrrrriiiiiiick!