You might also consider [RELEASE] Contained Motion Zones, which creates a virtual motion sensor based on contact sensors at boundaries. The idea is that if the door is closed, the person can't have left, so if there was ever a person in the room, there is still a person in the room until the door opens again, no matter how still they are at the moment.
I use this for bathrooms and bedrooms quite heavily, since the doors are often closed.
