There are also formations and barriers that protect the entire base and secures the doors. This adds a third layer of protection to the tunnels. In a pinch, the tunnels can turn into traps for intruders that try to use them.
Anyone who wanted to use the tunnels would need to have the keys with her or break down the door. From what Legion could tell, both fighting the captain for the key and attacking the door to break it down will be very difficult because the two entities are pretty powerful and dangerous.
She didn't show him where all the tunnels were. She only pointed out the two that were along the way to their destination to him.
The prison was on the second underground floor. This place was also home to the laboratory, the storage of divine flesh, and the vault securing divine artifacts.
