ChicagoEpguides reported that at 0:22:42 the voiceover from Howard da Silva at the beginning of episode 2 is mistakenly retained ("The signal from the missing ship grows stronger as the crew plummets to the underworld.")

Outro: There are other means of transportation besides cars, trains, boats and planes, you know. There are transmitted wave beams, for example. And next Sunday night a force of invading Vardans, who prefer this mode of travel, will materialize on The Doctor's home planet, Gallifrey. You can bet that getting rid of these creatures will take more than shouting "Vardans go home." [source: ChicagoEpguides]