Use one sword as a crowbar for the glued key, then take both keys and get the swords and try both the keys on the door, break the glass with the super acid for stuffs and giggles.
Obviously the one with the loose key is the one that works
It might be made of rock or metal, then again those elevator doors were sliced open pretty easily.
There may be more doors, and why didn't we just slice up the door?
The insides of the Ruins are Made of Tingalium, the most Stubborn metal ever