Visible crew/equipment: In "Cat from Hell" Amanda trips over the cat on the staircase, and falls downstairs. The white kneepads that she wears as she rolls down are quite visible in the slow motioned close-up of her. (00:40:30)
Visible crew/equipment: In the first part of the wraparound story, the film crew is reflected in the SUV Betty is driving as she pulls out of the parking space.
Visible crew/equipment: In the scene where the hitman is chasing the cat around the pool table, you can see the shadow of a tennis racquet on the floor as if being followed as a distraction for the cat to follow.
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