Here's the deal, I SUPPOSEDLY already picked up the brass ring from the dead body in the inner tunnels, but when I try to unlock the northernmost door it says it's locked... in a moment of desperation I even tried to use the xp cheat to get my mechanics skill high enough to pick it but I didn't want to lvl past 10 to do it.
Also of note I screwed up by leaving so the autosave is long gone for that zone. I'll invest another few hours to get back to that point but I'd rather not and I hope the game isn't buggy throughout the rest.