Why use stasis

The main uses appear to be, to put people to sleep for lengthy journeys, or if someone is infected with something nasty they can be put in stasis until a better treatment is available. Is it possible that the Engineer who was in stasis was in fact infected and also of the same psychotic disposition as Milburn became. Would it explain that maybe the dead SJ’s were killed by this rogue engineer. This could mean that they were not running from something, but to something. I think that this rogue engineer was stopped somehow from carrying out his intended plot of travelling to Earth. We know that there are other engineers ships that could take Shaw home. So if it was the engineers intention to destroy earth then surely this would be carried out by another crew. I think this gives some support to my theory that the engineer that is still alive is a rogue engineer. I think Shaw’s baby was just protecting its mum. The real question IMO at this point is whether the engineer already contained a life form. Is that also the reason why the engineer was in stasis in the first place as well?