Dowlee's comment notwithstanding, there are no signs of any tunnels, and so it seems clear that the party's only recourse is to proceed down the last flight of stairs. Everything looks clear to Flannad, so the group proceeds.
The staircase ends at a forty-foot-square room with a ten-foot-high ceiling. A slight draft blows into the room from a ten-foot-wide open passage in the far wall, directly across from the stairs. Two four-foot-diameter circular doors are set into the middle of the south wall. Each door is made of wood and framed with a ring of mortared stones. The westernmost door is closed and inscribed with a strange glyph. The easternmost door bears a different glyph but rests half-open. The half-open door reveals an iron rim of gear-like teeth, and dim light spills from the chamber beyond. Mounted to the walls of the room are twelve tarnished copper masks. The masks are two feet tall and cling four feet above the floor. Each one depicts a smiling gnome's visage. The soft giggling, chirping, and rustling noises seem to pour from the very walls.
[sblock=Flannad, Language]Flannad immediately recognizes the glyphs on the two doors. In fact, they are letters of the gnomish alphabet. The closed, westernmost door is marked with the letter 'J', while the half-open, easternmost door is marked with the letter 'A'.[/sblock]
(OOC: In addition to the updated map, I've put a diagram of the gear doors below. The first diagram shows only a door, while the second shows how the door rolls into its frame to open.)