When the engineer is driving back from the mountain,
he stops and picks up someone who is walking down
the road and starts talking to him, but when the
camera shows the car from long shot for the first
time, there is no one in the car other than the
engineer.
At the 1:31 mark, after the Engineer talks to Farzad about giving up the ghost, he drives away and the cameraman and director are visible reflected in the window of the car.