The Maelstrom Cloisters was an area of the lower levels of the Capitol located near the Outer Labyrinth. By the time of the Gallifreyan Civil War, it was a little-known ruin.
President Romana based her forces in the cloisters during the Civil War due to it having been forgotten by most Time Lords and the nearby labyrinth allowing for escape to the Outlands. Pandora's forces eventually found the base by following Narvin's blood trail and attacked, killing many of Romana's guards. Romana, Leela, Narvin, Matthias, Hallan and Annos were able to escape. (AUDIO: Fractures)