The Cryopods are what the UGI put criminals into or even people of importance for safe transport through enemy territory. They are incorporated into a Virtual reality that the person in the cryopod isn't aware they are in. For the criminals its a virtual reality that slowly breaks down the mind to extract information from without having to interrogate them. These pods are placed in a vacuumed and hermitically sealed storage facitility without any atmosphere.
They were initially intended to keep prisoners in stasis so that they don't have to feed them as well as keep them in hibernation with only their mind active they would spend eternity in sleep and would never wake up. The virtual reality put the prisoner into series of events that would break down the mind and as the prisoner overcame these events they would become more devastating and dangerous. In rare events the prisoner would be released from the pod into a chamber with no atmosphere and would suffocate to death. UGI kept these chamber pods secret as they broke human rights laws. They were also used to keep people of importance safe while transporting them through dangerous territory and the loss of the vessel's cargo would be minimal. Each UGI escape pod has these chambers onboard so that way the crew would be in cryo the entire ride home.