One important factor was, "did they sacrifice somebody early on?", for example in the actual evacuation from the ship. Once it is implanted in everyone's minds that individuals get sacrificed, it erodes trust, and makes everyone suspicious of everyone else. Of course, it's hard to distinguish between cause and effect in things like that.

There's a lot of details in the details, though, you might want to read the whole thing! :)

That makes sense. Nobody has a monopoly on violence so everyone wants to front-run their own demise by killing the person that will kill them with a small but non-trivial probability. Pre-emptive violence becomes rational in such an environemnt.