but it's possible the scene is an editing trick. Leah spent her time throughout The Wilds season 1 trying to piece together the mystery of their plane crash and what Nora had to do with it.
Now in The Wilds season 2, Fatin discovers the truth for herself and brings Shelby into the mix. Every one of them wants to get off the island
Then again, all of that could be part of phase 3 - seeing how everyone reacts to a new survival situation, especially if they all know the truth.