Continuity mistake: The ambulance stopped along the curb in front of the house, but the front bumper was about halfway between the tree and the front steps. When the taxi arrived, pulling alongside the ambulance, the ambulance's front bumper was next to the stair's handrail plus a police car was parked where the front bumper of the ambulance should have been. (00:17:41 - 01:19:45)
Continuity mistake: It wasn't snowing in the front of the house (e.g, when Ethan, Hallie, and Stephanie were going home; when the ambulance arrived; when anyone came in the front door), but it was snowing heavily in the rear of the house during scenes showing the Christmas tree. (01:18:24 - 01:20:42)
