When the mole machine begins to dig its way into the earth, the screw turns the wrong way.
The Sidewinder is virtually upside down in the pit, but scenes of the crew in the cockpit are right side up with a slight tilt to the right.
Near the end of "Pit of Peril", when the Mole returns to the surface with Scott and Virgil aboard, dust and sand can be seen pouring up from the ground on to the Mole's tracks - footage of the Mole tunnelling into the ground has simply been reversed.