The timetable is not the occupancy
A room scheduled until six is frequently occupied until seven, because a class finishes and a discussion continues. A study space with no timetable at all fills from five and stays full. A lab may be in use well outside any published hours. Building a cleaning route from a timetable produces a shift that collides with people in half the rooms and finds others empty for hours. Rooms empty for hours are as wasteful as rooms that cannot be entered at all.
The route is therefore built from observation over the first few weeks and corrected as patterns emerge. That is a mobilisation task and an ongoing one, since teaching patterns change each session. The crew reporting when a room's pattern has shifted is the mechanism, because nobody else in the building is watching occupancy from the perspective of somebody trying to clean it. Nobody else in the building watches occupancy from that perspective.
