Just a minor flaw that makes little difference to plot.
A thermos bottle contains heat or cold due to a layer of rarefied air (sometimes referred to as a vaccum) because long wave heat has difficulty passing through areas of few molecules.
Space is rarefied air with molecules widely dispersed. 4 humans and their associated microbes would generate heat that would adversely affect their health while surrounded by vacuum more so than the cold invading the container.
I think far more likely occupants packed into a small crate would displace the air necessary for 4 humans to breathe
Review of Evolution
