The cage containing the body of the late No.2 is sealed and then lowered down below into the the cavern, and little to the television viewers knowledge, onto a trailer of a lorry, a Scammell Highwayman Transporter in fact. But why? Why was it placed onto the trailer of a lorry? Why, for convenience. But the Butler knew that the lorry was there, knew that the cage had been lowered onto that trailer. Because the Butler walked round the lorry and climbed into the cab of the tractor unit, and drove it away, along the tunnel, and crashing through the closed gates at the end, with No.6, 2 and 48 in the cage.
It all had to have been set up previously, but by the Butler? Because if you think about it, the foot pedals, brake, accelerator, and clutch would have to have been adjusted to suit the Butler, otherwise he feet would never have reached the pedals!