Wouldn't a bunker be proof that they don't trust in J? I find it hard to believe that they'd create bunkers. That's not their style.
I dont think a bunker is the correct term, its a secret underground place for carrying on the global preaching campaign when it may be illegal to do so.
The JWs are expecting the UN to turn on religion and ban all religious activities sometime in the future. Most religions will comply, only JWs will carry on MOSTLY in secret. This is the reason for the secret underground compartments being secretly built around the world.
They stopped Nancy Chung formerbrother, after repeated warnings this stupid idiot still proceeded to go out on D2D, 30 years in solitary confinement done the trick, yes they can and do/will stop, go to Saudi Arabia/Iran/Sudan and organise some public door knocking work and find out how quick you end up in jail never heard from again!
Also N,Korea and dont forget China, also Russia now is under ban, but nothing can stop Jehovahs people. In all these places the preaching work continues just as Jesus said in all the nations.