CAR WAS STOPPED, PLACED IN PARK ON SLIGHT REARWARD INCLINE. DRIVER WAS ATTEMPTING TO ENTER A GATE CODE IN A BOX LOCATED NEAR THE DRIVERS SIDE DOOR. DRIVER COULD NOT REACH THE KEYPAD SO THE DOOR WAS OPENED AND DRIVER LEANED OUT TO ENTER THE CODE. THE CAR BEGAN ROLLING REARWARD AND DRAGGED THE DRIVER OUT OF THE CAR AND UNDER THE DOOR. THE VEHICLE WAS STOPPED BY ANOTHER VEHICLE BEHIND AND INLINE FOR THE SAME GATE OPENER. DRIVER SUFFERED SIGNIFICANT INJURIES AND WAS TRANSPORTED TO LOCAL HOSPITAL. NUMEROUS ELECTRONIC FAILURES PRECEDED THE INCIDENT AND HAD BEEN IN THE DEALERSHIP FOR CORRECTION BOTH BEFORE AND AFTER THIS INCIDENT. FAILURES INCLUDED AUX BATTERY, CPA+ INOP, KEYLESS ENTRY FAILURE AND OTHERS. PHYSICIAN IMAGES OF INJURIES PROVIDED UPON REQUEST. NO DAMAGE TO VEHICLE/S.