(Spoilers obviously)

Jackie’s death was alluded to and foreshadowed a few times (most specifically - Tai’s line about falling asleep/freezing to death a few eps before and of course the attempted ‘freeze out’ of Allie in episode 1). IMO she was figuratively and literally frozen out of the group, which will now allow for maximum chaos as she seemed to be the only one keeping sane until she went nihilistic in the wake of finding out about Shauna and Jeff.

I dunno. I think it was a LITTLE bit of a leap to think she wouldnt go back inside due to her pride but uhhhhh she was just locked in a closet and saw a dude get raped/nearly murdered.