CAR WAS PARKED ON A FLAT SURFACE, IDLING WITH GEARSHIFT IN THE "PARK" POSITION; DRIVER STEPPED OUT OF VEHICLE AND WALKED IN FRONT OF CAR. CAR SURGED FORWARD AND PINNED DRIVER AGAINST WALL. RESIDENT OF HOUSE CAME TO ASSIST AND COULD NOT GET GEARSHIFT OUT OF THE PARK POSITION - YET CAR CONTINUED TO SURGE FORWARD, CAUSING FURTHER INJURY TO PINNED PARTY.