The Key turns, and as it turns the device shows its contempt for the ravages of time: not one grain of rust, it seems, mars the surface of the mechanism within the pillar. The smooth motion and constant push have no clicking or rough jerks as of a clumsy gear-box lock, but a silent woosh as if pushing against a wind, no more.
The traceries light briefly, then dim, and where the light vanishes leaves darkness and space. The column is suddenly hollow, and no more solid than a shell, like a prop of scenery in some mummer's play. The main section falls back, pulling itself away from the key, and sliding into the main body of the column.
In the space beyond are stone steps spiraling downwards. They are unlike the stone of the room; while the crypt is made of solid stone, as smooth and unblemished as jade, these steps are like sandstone, rough and dusty with age. The corners of the steps, you notice, are covered in dusty cobwebs.
Beyond the light of this room, the stairwell is blackness itself.