Doctor Who: Terror of the Zygons (Part 4)

"Terror of the Zygon (Part 4)" is the fourth and final chapter in the "Terror of the Zygon" serial, which ran through episodes 17-20 in series 12 of the television series Doctor Who. The episodes originally aired in six parts on BBC1 from August 30th to September 20th, 1975. The serial was directed by David Maloney and written by veteran Doctor Who screenplay writer Terry Nation. In this episode, The Thal resistance fighters storm the Kaled bunker. The Doctor faces a strong moral dilemma and Davros makes his final move as the Daleks patrol the bunker corridors wiping out all opposition.