Cryogenic freezing is pretty much saying : get that b1tPillar of Winter , at the start of Halo 2 and at the end of halo 3. It is also possible to see an industrial freezer in Halo:Reacharound using the upskirt fly camera and going aboard the pillar of autumn. MC has a strong aversion to freezers as someone always takes advantage of it (namely: Cortana). This is also due to his tongue ending up on the freezer door whenever he wakes up defrosts.