First Aliera e'Kieron and Morrolan e'Drien were held captive in this place, as originally represented by a bare room with chains attached to the walls. Later Vlad Taltos and Teldra were prisoners in this place, and discovered there was much more than met the eye. The two discovered an exit to the room, a fabricated landscape, a controlled river of amorphia, and a large chunk of trellanstone. There are possibly more rooms, as Vlad's first physical confrontation with the Jenoine occurred in what appears to be an entirely separate room, due to the "uncomfortable-looking couch" present, which was lacking from the original. This was only a short distance from their prison space, however, according to Pathfinder, so it may well have been part of the same building.
It is clear, however, that the Jenoine do not deal with physical spaces the same way that humans do, so this distinction may be meaningless to them.
It is possible that this location exists only for the Jenoine to have a 'platform' from which to interact with Dragaera.