52. Doctor Who and the Silurians

After the the complete overhaul of Doctor Who last story, another paradigm shift occurs with the Doctor himself this story. Whereas the Doctor previously would often be the instigator of revolution, uprising, fighting, and even war; he now is trying to broker peace between two combative factions. Doctor Who now tells moral parables!

This story introduces a hallmark 3rd Doctor "monster", the Silurians, the original reptilian inhabitants of Earth. Wanting to reclaim their patch from the apes, conflict ensues. Of course the trigger-happy military in the form of UNIT are front and center to refute the Silurians claim. If UNIT is the rock and the Silurians are the hard place, then the Doctor is right in the middle of them!

Whereas in previous incarnations taking sides and helping to defeat the antagonists, this Doctor seems to be a pacifist. Abhorring violence, especially from the bullets ablazing of UNIT, the Doctor actually seems to be more on the side of the Silurians for most of the story.

In the end, it seems that the Doctor has reached a détente between the two only for the Brigadier to blow up the entrance to the cave and burying the Silurians once again. This apparent betrayal of the Doctor by the Brigadier is the moist shocking moment of the whole story and sits like salt in the wound for the Doctor. This is the first time that one of the Doctor's companions has ever betrayed him in such a way. The closing shot of the Doctor's face truly cuts you to the core.

http://en.wikipedia.org/wiki/Doctor_Who_and_the_Silurians