It's logical fallacy on the grounds that Betty's wailing can't be specifically connected to being controlled by the devil. There is no proof that the devil caused her wailing and there lies the flaw of her rationale. Wailing by a ten year old can be caused by anything. Betty is wailing in light of the fact that she is terrified of Abby and knows she's equipped for insane extravagant things, she doesn't know why she's attempting to help Abigail with her plan. Betty is extremely frightened.
