Continuity mistake: In first segment of the wraparound story, Betty walks inside with her bag of groceries. We see the groceries sticking out of the top of the brown paper bag, and between shots, they are positioned differently. (00:03:10)
Continuity mistake: In "Lot 249," when Andy is watching Bellingham snip open the dried, ancient mummy, the bandages hanging over the side of the mummy's coffin change position, and some bandages disappear and reappear from the side. (00:12:35)
Continuity mistake: In "Lot 249," Susan takes the Zuni Fetish out of it's box. Between the closeup of her removing the fetish, and the next wideshot, the items on the table (toy cars, fruit in the bowl, etc.) change position. (00:14:55)
Continuity mistake: In "Lot 249," when Susan confesses to Andy that she saw who killed Lee, between shots the way she holds her brandy glass changes and also the position of the pearl bracelet wrapped around her wrist differs. (00:22:30)
Continuity mistake: In "Lot 249" during the scene where Andy has Bellingham tied to the chair, the items on top of the fireplace constantly move around. The lamp keeps moving and so do the ornaments. In one shot all the items shift, etc. (00:26:25 - 00:30:00)
Continuity mistake: In "Lot 249" Andy has Bellingham tied to a chair, and he then brings over a box of paper and dumps the sheets all around the chair. In the following shots, the sheets of paper spread out change position. (00:26:35)
Continuity mistake: In "Lot 249" Andy sets the ancient Egyptian scroll alight. In the first shot, just the right bottom corner of the scroll is on fire, but in the next shot the whole right side of the scroll is blazing. (00:30:50)
Continuity mistake: In "Lot 249" Andy sets the ancient Egyptian scroll alight. As he sits there in front of Bellingham talking to him, Andy keeps alternating from holding the scroll at the middle to at the edge, between shots. (00:30:50)
Continuity mistake: In "Cat from Hell" Amanda is walking downstairs, when the cat trips her. As she starts falling her legs face the camera. In the next shot her position has changed and now her head faces the camera. (00:40:30)
Continuity mistake: In "Cat from Hell" Carolyn locks herself in her room with the cat. The cat then attacks her and kills her whilst she is sleeping. It is then shown leaving the room, but the door was locked beforehand. (00:41:15)
Continuity mistake: In "Cat from Hell," when Halston pours himself a glass of whisky, he notices the bloody scratch on his shoulder. Between shots the level of his drink keeps lowering then rising back to the same level as before. (00:48:25)
Continuity mistake: In "Cat from Hell" Drogan is attacked by the cat and suffers a heart attack. He then drops his pill bottle and all the pills spill out over the floor. In the next shot the pills and the bottle are differently positioned. (00:55:15)
Continuity mistake: When Betty is snipping some flowers in the wraparound story, just before the "Lover's Vow" story begins, the buds are closed on all of the flowers. However in the next shot most of the buds on the flowers are wide open. (00:55:30)
Continuity mistake: In "Lover's Vow" Wyatt leaves the bar after firing Preston, leaving his drink and newspaper on the end of the bar. In the next shot the paper has changed position and in the next shot it completely disappears. (00:58:50)
Continuity mistake: In the final segment of the wraparound story, Timmy drops his marbles and Betty falls backwards onto the spikes, dropping her keys. In the next shot as Timmy reaches for them, they are in a different position. (01:25:35)
Continuity mistake: In "Lover's Vow", as Preston evaluates the deep, nasty scars he has on his chest from his encounter with the gargoyle, he turns away from the mirror for Carola to tend the wounds. But, when Carola starts treating the wounds, the deep wounds are now shallow streaks of blood rather than deep scars.
Answer: While it's not explicitly said in the film, it seems Preston breaking his vow turned her back into a gargoyle. She didn't have a choice and since he swore on his life never to say anything, she had to kill him. Plus, the stories in the book don't have happy endings.
Bishop73