Outdoor soil in an indoor room
Sports and grounds equipment brings in mud, grass, sand and water, and it arrives in bulk at the end of a session rather than gradually. The floor takes most of it, but it also transfers to shelving, to the walls where equipment leans and to the door approach, which is often where the worst of it is deposited as gear is dragged through. Bags and kit left on the floor keep the moisture in contact with the slab for days.
Because the soil is abrasive and often wet, dry removal followed by a wet method is the sequence that works, and the door approach usually needs a shorter interval than the room itself. Matting at the entry helps considerably, though in a store used by students it needs to be robust and it needs somebody responsible for lifting it. Without that, a mat simply holds the mud where the next student will walk through it.
