If snipers are still allowed it won't be hard for the allies at all. 2 snipers could kill off half of the Germans before any allies entered the tunnels.

------------------
"At basic you learned out of a book, I'm going to teach you things they never put in the book, and probably never will" -Sands of Iwo Jima
Stryker's Medal Of Honor: Allied Assault headquarters
WWII wargaming forums