OneWayFacility
Seals facility entrances behind you after a grace period. Exiting requires another exit or a Key, Very Configurable.Upon entering the facility from any entrance, the door you entered will lock behind you. A grace period is granted so that you may instantly leave if a monster or something appears at the entrance. After the grace period the door is sealed and you will have to find another door to exit the facility.
This mod intends to force you to go through the facility rather than picking up a few items and leaving right away. Alternatively you may use a key (if enabled in config) to unlock a sealed door. After exiting the first time you can re-enter and leave from any exit as if the mod isn't even there.
The mod automatically checks for dead ends and leaves any fire exit or main entrance open if it detects there would be no way to escape after sealing.