Australia bethel has underground tunnels also!
It is where all the home brew kits are secretly kept! (I'm not joking either)
Slightly off topic - but I've been told by a couple bethelites that there are a lot of guys in NY bethel that put false-backs into their closets. Not just for home-brew, but also to hide their still for making brandy from rotten fruit from the farm.
I wouldnt' read too much into the tunnels...but their withdrawl from the urban areas is the first sign of a group that's about to become radicalized.