Visible crew/equipment: When Michael Douglas leaves the car rental there is a guy across the street behind a bus conspicuously watching everything. (01:15:45)
Continuity mistake: When Michael Douglas is listening to Alex's tape it's midday when he enters the East River Drive underpass and comes out the sun has clearly set. Alex's tape doesn't skip a beat. (01:17:00)
Visible crew/equipment: While Michael Douglas is listening to the tape in the attic there is a reflection in the window of someone who looks to have long blonde hair, just above and slightly to the right of the lamp. (01:20:40)
Visible crew/equipment: When Michael Douglas goes to the police for the first time, after he gets the tape, when he is talking to the policeman watch for the reflection of the boom mike to the right of the cop's head in the trophy plate. It's beautiful and in every shot. (01:22:40)
Continuity mistake: When the little girl is playing in the back yard outside the rabbit cage it's winter, not a leaf in the tree she is under. In the very next shot as they get into their car all shrubs and trees in this shot have their leaves. (01:23:10)
Continuity mistake: The little girl appears to have been given a haircut after we see her at the empty rabbit cage, most apparent when we see her the following morning. (01:27:00 - 01:30:30)
Continuity mistake: Playland, Rye NY in the spring, summer and autumn. Alex and the girl walking to the Dragon Coaster. It's spring with the leaves in bloom. Then in stock footage of a different roller coaster being pulled to the top, it's fall with the leaves a golden yellow. Then in other stock footage, the trees are a lush summery green. (01:36:35)
Audio problem: There's no doorbell or buzzer sound when Michael Douglas presses the button on Alex's door. (01:41:20)
Revealing mistake: Inside Alex's apartment when the stunt double breaks the glass, you see by the way it breaks that it is untempered glass. This first mess is cleaned up and then they put down other stuff that looks tempered but isn't real glass at all. (01:42:00)
Revealing mistake: As Glenn Close is being choked, Michael Douglas is holding her throat very loosely. (01:42:20)
Visible crew/equipment: You see the reflection of the cameraman right in the center of the tea pot as Michael Douglas makes Anne Archer some tea before her bath. (01:49:20)
Continuity mistake: In the famous bathtub scenes there's a close-up of Alex's feet with blood dripping on her right foot. Later when we see her in the tub the blood is in a different spot on her foot. (01:51:40 - 01:53:15)
Continuity mistake: There is a lot less blood on the knife after Glenn Close flings it than there was in the shot before when you see her fall. (01:51:50)
Continuity mistake: The water level was almost but not quite overflowing the brim of the tub when Michael Douglas is pushed in, and the faucet was still running, so there should have been more water on the floor. (01:52:25)
Continuity mistake: At the end of the film during the final confrontation when Michael Douglas first forces Glenn Close into the bath tub only her ankles are over the edge of the tub, however in the very next shot her knees are dangling over the edge. (01:52:40)
Continuity mistake: In the scene in the tub, Glen Close's feet start out filthy, then they become clean as a whistle when she is flailing from her knees, then by the end of the scene they're disgusting again. (01:52:40)
Revealing mistake: In the final confrontation scene Glenn Close comes out of the bath tub and raises her arm, the scene cuts to the gun and when it returns to Glenn Close you can see the fabric of her dress has changed to a thicker one to accommodate and cover the squib needed for her gunshot wound. (01:54:05)
Continuity mistake: Glenn Close changes her dress from the shot where she gets up out of the tub to the next shot where she is shot. The bloodstains on the collar are different. (01:54:10)
Continuity mistake: One scene has Glenn Close in bed shot from profile, and the sheet in down exposing her breasts. The film cuts to a frontal shot and the sheet is up around her neck. When it cuts back to profile, the sheet is down again.
Other mistake: Dan and Alex go to what looks to be Alex's apartment after meeting at the office and going for a drink. After romping around in bed, they go dancing, and on the way back through the meat-packing district, she leads him to the door of her apartment and tells him she lives upstairs and he says something like, "this is your building?" It seems odd as they were just up there having sex.
Answer: Because she is insane! And she picked the lock. By murdering the innocent pet bunny rabbit Alex was sending a message. She won't be ignored! She's just letting Dan know that she can get to him, or in this case his family (daughter's pet), anytime she wants to. He's not safe.
Alan Keddie