| GMS compound|
GMS compound is the first major dungeon the player visits during Underrail storyline. It is located in Lower Underrail, and can be accessed via the Lower Underrail exit from South Gate Station, by heading north from the station platform on SGS level 1.
The player travels there during Gorsky's task and is tasked with finding a way to open the sealed door on the first level of GMS compound.
Level 1: Offices
The initial level, some dusty old offices full of rathounds and junk. A large sealed door is located near the entrance. To the west is an unpowered elevator, to the northwest are stairs and the power generator for the whole compound is also on this level.
An Omni-Tool can usually be found somewhere on the first level, and it proves useful as the whole compound proper is full of accessible ventilation shafts. Just remember that rathounds are more than capable of crawling inside the same ventilation tunnels.
During your mission here, Gorsky's team will be waiting near the entrance.
GMS Compound - Cave
An adjacent watery natural cave with even more rathounds in it. Some Mindshrooms also grow here.
Level 2: Storage
This level is largely devoid of living creatures. Armed Sentry Bots roam around. Breaking in to the storage rooms can yield some useful loot.
The stairway leading down is blocked by rubble, so the player has to find another way to advance.
Level 3: Commons
This level consists of a relatively clean living area with cafeteria, and some storage rooms. The elevator on this level is broken, but it can be repaired with sufficient mechanics skill. This level has been recently overtaken by raiders, coming in from the adjacent caves.
Burrower nesting area near the GMS compound.