Something I just thought of: So nobody has told Lydia anything yet right? Even though they suspected she might be turning. Even though she was lost in the woods for two days and can’t remember a thing, and they have no idea what she was up to in that time. Even though she’s been in the middle of the crossfire at least twice now. Nobody has thought, oh, hey, maybe we should sit Lydia down and explain what’s been going on and what could possibly be happening to her? So instead, she doesn’t know what’s going on and will probably be completely terrified when she realizes something could be very wrong with her.
Okay then.

