PULLED INTO A PARKING SPACE AND PLACED THE VEHICLE IN PARK,TURNED THE VEHICLE OFF, REMOVED THE KEY AND EXITED THE VEHICLE. WHEN RETURNING TO THE VEHICLE WITHIN 5 MINUTES, THE VEHICLE HAD ROLLED BACKWARDS 25 FEET AND HIT 2 PARKED CARS. I UNLOCKED THE VEHICLE, ENTERED IT AND STARTED THE CAR TO RETURN TO MY ORIGINAL PARKING SPACE SO I COULD CALL THE POLICE TO REPORT A FENDER BENDER. I WILL BE CALLING MY DEALERSHIP IN THE MORNING TO HAVE THE VEHICLE INSPECTED FOR SAFETY. IN THE MEANTIME I PARKED THE VEHICLE AND APPLIED THE EMERGENCY BRAKE AS AN ADDED PRECAUTION.