Zael comes here imprisoned two times, both by Jirall's accusations. The first time, he is brought here with the other mercenaries to find that Lowell and Syrenne were also imprisoned. The second time he comes alone, but he is rescued by Calista, who helps him escape and clear his name.
The being imprisoned in the center of the dungeon is Berith. During the third assault, Zepha and Zesha release it from its restraints and it escapes to the Turret Basement, where it fights Zael and Calista.