I am a little conflicted about this. On one hand, I feel like the way she acts at the beginning makes sense. She is a bullied kid with no powers, and her superpowered sisters can't do anything let alone her. I think it would have been fine if she hated everyone for how they treated her, but there were a couple of people she was friendly with, the Archiver and the Captain, and she just runs away, destroying the portal, condemning everyone to die or become a slave.
So, overall, I would have liked to have the option to try to help, though probably that wouldn't have changed anything.