ON OCTOBER 1, MY MOTHER (PASSENGER) AND I WERE INVOLVED IN A ROLL BACK ACCIDENT AT MY APARTMENT COMPLEX. I PUT THE VEHICLE IN PARK AND EXITED THE VEHICLE. I REMAINED OUTSIDE OF THE VEHICLE FOR 1-2 MINUTES. I RETURNED TO THE DRIVER'S SIDE, OPENED THE DOOR, AND PROCEEDED TO ENTER THE CABIN. UPON OPENING THE DRIVER'S DOOR, THE VEHICLE BEGAN TO ROLL BACK, EVEN THOUGH THE CAR WAS IN PARK. I WAS CAUGHT BETWEEN THE VEHICLE DOOR, WITH HALF OF MY BODY/EXTREMITIES (THE RIGHT SIDE) IN THE CABIN, AND MY LEFT EXTREMITIES OUTSIDE OF THE VEHICLE. I WAS DRAGGED 10-15 FEET. MY MOTHER WAS IN THE FRONT PASSENGER SEAT WITH HER WITH SAFETY BELT. THE VEHICLE HIT AN EMBANKMENT (WITH A 6-7 FOOT DROP) THAT LEADS TO A GAZEBO THAT COVERS OUR MAILING CENTER. THE REAR OF THE VEHICLE CRASHED INTO THE WOODEN FENCING AND THE ROOF AND COLUMNS OF THE GAZEBO. THE FRONT END WAS STUCK IN THE EMBANKMENT; THE REAR END CRASHED INTO THE ROOF, BUT WAS SUSPENDED ABOVE A 6-7 FOOT DROP. POLICE AND FIREMEN ASSESSED THE SITUATION, AND SUSPECTED THAT THE INCIDENT MAY HAVE HAPPENED AS A RESULT OF A MALFUNCTIONING TRANSMISSION AND/OR BREAK SYSTEM. NO FAULT WAS DETERMINED IN THE INCIDENT.