Tegan's departure is one of the saddest in the show, next to Adric's death.
Revelation of the Daleks was a 6th Doctor (Colin Baker) story originally broadcast in 1985 It's one of the oddest stories the show ever produced The doctor and Peri discover a funeral home on an alien planet has been taken over by Davros[...]
revelation of the daleks Archives
That situation will be remedied this year when BBC Books publishes former script editor Eric Saward's novelization of those stories: Resurrection of the Daleks…
https://youtu.be/B9NttGB9oOwVideo can't be loaded because JavaScript is disabled: The Doctor & Davros Meet Again | Resurrection of the Daleks | Doctor Who (https://youtu.be/B9NttGB9oOw)
and Revelation of the Daleks:
https://www.youtube.com/watch?v=z32WpsHyJgwVideo can't be loaded because JavaScript[...]