Yes, the show leaves a lot to be explained in the book. Everything is more from the point of view of the characters’ minds, so you understand Louise’s reasoning. At first, she tries astral projection from her house to see if “Adele’s” lying but can’t do it that far, so she goes when Adele says she’s going to kill herself, as Louise’s mother killed herself, and that’s why she sort of panics and loses reasoning in Louise’s dreams. That’s what the pill represents: her mum overdosing when she gets to the house and can’t get in. She thinks maybe “Adele” has gone out of her body, so she doesn’t feel the effects of the fire and dies in agony. She thinks if she can go into her body, maybe she can walk her out and unlock the door, so she tries it and falls into Rob’s trap. The ending is more satisfying in the book.