There have been two previous ww2 events in the tunnels.
The First one was run by C.I.A The Boryszyn Loop - 24th January 2010
http://www.youtube.com/watch?v=RvFJVfihzuI
Video made by bedsnherts
The second event was run by Oddball. (who did the video) Anarchy under the Eagle - 21st August 2011
The Video is 48 Minutes long, But it Shows the Tunnels in good detail.
http://www.youtube.com/watch?v=TJkjuViLj1c
The video also shows vehicles in the tunnels, @ 11:30 mins and how they move. This is planned for the Fuhrers escape game.
Also a captured panzerschrek at 30:20
"Take that you rotton helping of strawberry flan!"
Joseph Porta to "strawberrys and cream", in the sven hassel book ,ogpu prison
May also have the tank running down there so keep your toes clear 
Free speech is expensive these days!
