Holding chamber
From Halopedia, the Halo wiki
Holding chambers are Covenant prison chambers.
They are found within High Charity and in other Covenant ships, and are used for holding prisoners. They have some sort of energy barrier on the front, which can be deactivated with a switch, in the case of the CCS-class Battlecruiser, or in other, as of yet unknown, methods.
Trivia
These holding chambers are similar to those used in the buildings on Uprising near Installation 05's Control Room, and it is possible, if not probable, that the Covenant designed their holding chambers around the Forerunner chambers.
