The Devil's Switchback

You enter a circular chamber carved into the mountain's heart. Basalt walls sweat with orange heat, while thin veins of lava pulse beneath iron grates in the floor. Four archways surround a horned iron pedestal, and each archway is sealed by a rotating gate covered in red, black, and gold glyphs. A cold iron bell rests on the pedestal. Beyond the gates, corridors twist away and return at impossible angles, while black mirrors reflect the room with one deliberate detail changed in every image. Somewhere deeper in the mountain, a bell answers with a distant metallic groan.