Leela is imprisoned in a condensation chamber within a steamer. (TV: The Sun Makers)
A condensation chamber was a device used in steaming, a form of execution. The victim was placed in the chamber and entered the steamer by travelling along a track automatically. High-pressure steam would fill the chamber, scalding the victim.
Leela was put in a condensation chamber for execution. After K9 stopped the flow of water, the Fourth Doctor entered the steamer and pulled Leela from the chamber. (TV: The Sun Makers)
