CONTRACTOR WAS A PASSENGER ON 340 MANTRIP. WHEN APPROACHING AN AIR DOOR THE VEHICLE WAS STOPPED TO PULL THE ROPE THAT OPERATED THE SET OF ELECTRICAL CONTACTS TO THE AUTOMATIC AIR-OPERATED VENTILATION DOOR. AS VEHICLE STARTED THROUGH THE DOOR ABRUPTLY BEGAN TO CLOSE. IT STRUCK THE VEHICLE AND SLIPPED OVER INTO THE PASSENGER COMPARTMENT AND STRUCK THE CONTRACTOR.