4. The Death Of Adric
The second companion to be killed off of Doctor Who was Adric. The young companion was always a target of debate. He was actually wonderfully paired with the Fourth Doctor. Adric stowed himself on the TARDIS and travelled with the Doctor since. But after Tegan and Nyssa came aboard, he felt teased and alone, and wanted to go home, back into E-Space. This caused a big argument between him and the Doctor, as getting E-Space was tricky. It's a Cyberman story where Adric meets his fate, called Earthshock. There are many people that most likely have not seen this episode as they haven't really explored the classic series in full yet, so I won't go into details about how and why. But it is a rather sad ending, no matter how people feel about the character Adric, with the end credits playing out in complete silence.