I spent 2 years in that building and this is the first I ever heard of the tunnel.
Anything is possible. To be fair I never tore any walls down.

We spent many hours in that basement. When I had it, we had a 2nd baroom down there. At closing time, we moved the topless dancers and customers down, until time to open again in the AM. Also had a few poker games down there.
We closed at 4AM and opened at 6AM.