STARTING TO BACK OUT OF MY DRIVEWAY, I STOPPED AND THOUGHT I HAD SHIFTED THE ROTARY AUTOMATIC TRANSMISSION KNOB TO THE PARK POSITION TO GO INTO THE HOUSE AND RETRIEVE AN ITEM BEFORE CONTINUING. APPARENTLY, I DID NOT GET THE KNOB CORRECTLY IN TEH PARK POSITION, AS I STARTED EXITING THE VEHICLE WITH THE DOOR OPEN, THE TRANSMISSION WAS STILL IN REVERSE AND STARTED ROLLING BACKWARD. I RE-ENTERED THE VEHICLE TO APPLY THE BRAKE, BUT NOT UNTIL THE OPENED TRUCK DOOR HAD COLLIDED WITH MY GARAGE WALL, CAUSING DAMAGE TO THE TRUCK DOOR AND THE GARAGE WALL. I FELT FORTUNATE THAT I WAS NOT PINNED BETWEEN THE DOOR AND THE GARAGE WALL BEFORE I WAS ABLE TO GET BACK IN THE VEHICLE. THE KNOB SHIFT CONTROL IS NOT VERY INTUITIVE AND I BELIEVE CAN LEAD MORE FREQUENTLY TO DRIVER ERROR. IT WAS ALSO SURPRISING TO ME HOW MUCH ACCELERATION AND FORCE OCCURRED WITHOUT APPLYING ANY PRESSURE TO THE GAS PEDAL.