They left no bodily mark on their torture subject, but the being was screaming for mercy within but an hour, maybe less. The chamber was pitch black, it was not warm, nor cold, the walls were so soft they could practically not be there, though they were strong to hold the subject in, and there was no gravity, so no pressure on the body. Total sensory deprivation. The subject was not even able to hear their own voice.
When cruel people want to interrogate humans, they do the worst KIND of harm, they do not allow the humans any physical sensations at all.
However, they learn the hard way what OTHER humans will do to those that torture their kind in this way. -- Anon Guest
All it takes is one escapee. One survivor. One who gets out and tells their story to someone who listens. Then the rest of the Alliance learns of the horror of the Quiet Room.
Anything that was once therapy can be torture, and vice versa. This therapy was a derivative of the Sensory Deprivation Chamber, but amplified to the extreme. Sound baffles and complete darkness was just step one. No gravity, so the victim could not feel the pull of the world. Then, the true nastiness, forcibly interrupting the sensory feedback so that the conscious mind had no input at all.
Cavers know of the hand in the darkness, but even that is shut off with a very interesting chemical cocktail. Only the survivors knew the true terror of nothing.