Doctor Who (1963)

Chaos erupts as Davros releases the Movellan virus, killing the Daleks and loyal station troops alike. The Doctor tries to stop both sides, but Davros escapes in an escape pod, vowing to build a new Dalek army under his command. The Doctor destroys the station to prevent the spread of the virus, barely escaping with Tegan and Turlough. Returning to London, Tegan, shaken by the relentless death and destruction, tells the Doctor she can no longer travel with him. The Doctor watches silently as she walks away.