It’s fully self contained including aire scrubbing and cleaning like a submarine with hydroponics…..
The perimeter is miles from site and it’s burrowed into mountain and valley. The security door is 2 feet thick and where there are escape tunnels I am sure won’t be easy to find.
Best you could hope for is to loot the top surface stuff but I am sure they thought of that… probaby gun placements that would make it costly…
Their problem will arise from how they treat others… a revolt… already in town most won’t sell to them.