Doctor Who is driving and the Brigadier is a passenger as they are heading towards a brontosaurus. They pass under the dinosaur. However, once they reach their destination. suddenly the Brigadier is in the driver's seat and Doctor Who is the passenger.
When The Doctor is rescued from General Finch (John Bennett) by
Brigadier Lethbridge Stewart (Nicholas Courtney) the mark where The Doctor is to stand during the confrontation is visible. A piece of debris.