You can block the underground bunker with just a few walls, and as there are narrow & long tunnels you can build a lot of layers.
It's easy to keep other players from exploring these new parts of the map that way (and from the loot that is only spawning there)
Please consider changing (some of the parts) in the bunker so it's not possible to build on - for example like it was changed for the Livonia prison by adding a different kind of floor by the prison-entrance
The new patch looks amazing and it would be a shame if players finally make it into the bunker just to be welcomed by dozens of gate-layers