I liked the suspense but I have a suggestion for a different, sinister ending which doesn't involve clowns!
AFTER STARTING THE CAR, MIKE GETS BACK OUT AND SHUTS THE DOOR.
CUT TO: INT. CAR
MIKES WIFE IS "ASLEEP" IN THE PASSENGER SEAT
CUT TO: EXT. COUNTRY LANE
MIKE WALKS AWAY FROM CAR WHISTLING WHILST JUBILANTLY TOSSING/CATCHING ROHYPNOL BOTTLE.