Country & Year: (Hong Kong 2007) (Many Thanks to ZoneDaiatlas)
In a closed room with some dim light at the suburbs, a man and a woman are lying on the floor. They are in a coma. And, there is a small knife stabbed into the stomach of the man. The woman wakes up. She finds that the door is locked.
From the crack between the door and its frame, she finds a door key on the ground outside.....