I STOPPED MY CAR AT TOP OF MY STEEP DRIVEWAY,PULLED UP EMERGENCY BRAKE,PUT CAR IN PARK BUT LEFT CAR RUNNING TO LISTEN TO SONG ON RADIO. I SAW A PROBLEM IN MY YARD,OPENE THE DOOR, TOOK CARE OF PROBLEM THEN GOT PARTIALLU BACK IN THE CAR TO CUT OFF ENGINE. AS SOON AS I SWITCHED OFF THE ENGINE THE CAR STARTED ROLLING BACKWARDS, STILL IN PARK WITH THE EMERGNCY BRAKE UP AND MY LEFT LEG DRAGGING THE GROUND AS IT ROLLED ACROSS THE STREET AND INTO MY NEIGHBORS BEDROOM. IT IS A VERY COSTLY ACCIDENT. ALL WAS FINE UNTIL I CUT OFF THE ENGINE SO I THINK THAT CUTTING OFF THE ENGINE CAUSE A GLITCH IN THE ELECTRONIC TRANSMISSION TO CAUSE IT TO GO INTO NEUTRAL WHILE STILL SHOWING IN PARK.