Continuity mistake: Back at Michael Douglas' apartment, Sharon Stone uses his ice pick to break up a big hunk of ice for their drinks. In front of her is a tray with various items and loose change in it, with a padlock and a piece of paper to left of it. Everything in the tray and the piece of paper move throughout the scene without anyone going near them. (01:03:55)
Continuity mistake: When Michael Douglas walks into Jeanne Tripplehorn's office there's a large plant more than one foot to the right of the lamp by her window. Later in the scene this plant is moved to the left where it's almost in front of the lamp in her close-ups. (00:13:25)
Continuity mistake: As Sharon Stone sits for questioning at the police station, the coffee pot on top of the coffee machine rotates throughout the scene without anyone leaving their seats. (00:27:10)
Continuity mistake: As Jeanne Tripplehorn talks with Michael Douglas her hair is combed differently in the close ups. When we first see her it's combed totally to the left, then in the close-ups it's combed back and to the left. (00:13:55)
Continuity mistake: When Roxy tries to run over Nick the left front light is broken off - in the next scene it is back on.
Continuity mistake: At the end of the movie when Michael Douglas and Sharon Stone relax in bed contemplating their future together and the black lamp on the left side of his bed changes the direction that it's pointing in throughout the scene without anyone going near it. (02:01:00)
Continuity mistake: As she walks into Michael Douglas' apartment, Sharon Stone drapes her jacket over the center of one of his kitchen chairs. Later in the scene she walks over and gets the jacket and it's draped over the left side of the chair. (01:03:20 - 01:04:55)
Continuity mistake: At the beach house Sharon Stone is sitting in direct sunlight as she speaks to Michael Douglas about Jonny Boz yet in all the close-up shots, even when he walks between her and the sun, she's never in direct sunlight. (00:11:00)
Continuity mistake: Michael Douglas and his partner go up to Sharon Stone's beach house to get her to come in for questioning and the large clasp on her gold necklace moves between shots without being touched. (00:21:20)
Continuity mistake: When Michael Douglas first sees her at the beach house he says, "Miss. Tramell?". If you closely at the shadow cast by the railing it's obvious that at least an hour has gone by between shots as he walks down to talk to her. The lounge chair has also moved between shots. (00:10:50)
Continuity mistake: When the detectives ask Catherine to go in for questioning, she has her hair down. Then, a minute later, she comes out with her hair up. Problems: one, there's no way Catherine could do that on her own, and no-one else is in the house; two, even if she could it would take much more than a minute, say thirty minutes.
Continuity mistake: When Nick and Gus are waiting for Catherine to get changed, out of the corner of his eye, Nick sees Catherine step, naked, into a white dress, then, again, she steps into the same dress.
Continuity mistake: No one goes near it but during Sharon Stone's questioning at the police station the brown coffee cup in front of Wayne Knight rotates between shots. (00:25:15)
Continuity mistake: On Jeanne Tripplehorn's desk, there's a large spherical polished rock that has been moved around between shots as Michael Douglas has his first interview with her. (00:14:00)
Continuity mistake: When Sharon Stone sits down for questioning at the police station, a black folder on Wayne Knight's desk moves next to the brown coffee cup between shots. (00:24:55)
Continuity mistake: As Sharon Stone sits through questioning, the retractable light on the right of the camera is moved to the side toward the end of the scene without anyone going near it. (00:28:40)
Continuity mistake: In an overhead shot back at her house, Sharon Stone walks away from her pool towards her car which is in total shade. In the next shot as she gets in the car she's in sunlight. (00:39:35)
Continuity mistake: When Michael Douglas and his partner are in the diner, the cap on the Tabasco sauce bottle is off. A second later, it is on.
Continuity mistake: At the end of the movie Michael Douglas goes back to his apartment to find Sharon Stone waiting for him and the chair and the items on the kitchen table move between shots without anyone going near them. (01:59:30)
Continuity mistake: Jeanne Tripplehorn walks into her apartment and Michael Douglas is there asking questions about her and Sharon Stone in college. If you look closely the pillows on the couch on the left of the screen move from the time she opens the door to when she walks into the apartment. (01:38:35)
Answer: No definitive answer is given in the film. Catherine didn't need a reason for anything that she did. As for Beth, that was just a bonus, or a coincidence. It could be argued that Catherine targeted Beth, and Nick was just unfortunate to be involved with Beth.
ChristmasJonesfan