Ancient Bunker Walkthrough
The Ancient Bunker is on Oasis V in the Nameless Star system, tied to the "Mercatum Tabula Officiale" quest. This one is not a logic puzzle. It is a two-part environmental clear: first you vent a room full of toxic gas, then you deal with the automated defenses guarding the way out.
Clearing the Melting Venom Gas
The bunker is flooded with toxic "Melting Venom" gas, and you have to restart the ventilation to make it safe. Open the front gate and rush to the boiler room. Interact with the valve there, then go to the adjacent room to retrieve the valve. Bring it back, reinstall it in the boiler room, and activate it again. With the valve seated, move to the next room, interact with the cogitator, and restart ventilation. That clears the gas and lets you move through the rest of the bunker.
Bypassing the Turrets
On your way out, four automated turrets switch on. You have two ways to handle them.
The straightforward option is to fight all four. The cleaner option is to skip the firefight entirely: head to the terminal in a small room to the north-east of the turrets and pass a Tech-Use check to shut down the security system, which ends combat on the spot. The Tech-Use shutdown pays out very little experience, around 11, so if you are hunting XP the fight is the better return.
Loot
Two pickups are worth your time inside the bunker.
A Worn Seal sits in a locker, and you need it for the "Mercatum Tabula Officiale" quest, so do not leave without it. The standout reward is the Sworn Protector, a unique Iconoclast lasgun. It is in a storage room east of the Vox-Caster room, locked behind an Officer Key. That key is on a corpse in the northern shower room, so sweep that area first, then double back for the lasgun.
More of the campaign's gated areas are covered on the puzzle and walkthrough hub.