Continuity mistake: When Sue climbs the dark staircase to talk to Mr K they are interrupted by a phone call. The phone rings four times before Mr K answers. But when she sees this scene in the cinema later Mr K answers the phone after only two rings.
Continuity mistake: When Sue is talking to Mr. K, the phone rings four times before Mr. K answers it. But when Sue watches this scene on the cinema screen later, Mr. K answers the call after two rings.