Inferno

The genius of "Inferno" is that it's self-containing. Had the idea of the Doctor visiting a parallel Earth been hatched a couple of years on, the production team could have done it in half the time by subverting the roles of characters we already knew well; the scatty Jo Grant, the slightly buffoonish Brig, the lovable Sergeant Benton. "Inferno" instead came at a time when the Nazi-ist alternate world stereotypes weren't actually that far removed from their real world counterparts. The Brigadier is still quite a harsh, military figure only two stories on from having blown up the Silurian caves, Liz is the hardest, some might say butchest companion we have yet known and Benton is still new, mentions of ballroom dancing and kid sisters still some way away.

But the contrast isn't just drawn by making the other world characters members of an utterly ruthless dictatorship; cleverly, the similarities are inherent in the softness of the parallel worlders, as well as the hardness of the real world characters: Section Leader Shaw wondering what her counterpart is like, for example, or the Brigade Leader breaking down when he has no thugs to defend him. The production manages to pull off an initial dramatic contrast with the characters we expect to see, but then later allow a combination of their similarities with those characters and their more human qualities to make us sympathise with them. In the end, we realise that despite the mercenary nature of the "other" world, the people in it are essentially the same ones we know and love; Section Leader Shaw is still Liz, with her career and outlook distorted into something aggressive by the world she lives in, and the alternate Greg and Petra are still victims of a world that straightjackets them; notice that the hostility and prejudice shown to Sutton because of his background occurs almost identically in both realities.

Where, though, is the Doctor? His absence from the parallel world is just one of the unanswered mysteries of "Inferno". Some say he is the dictator, but that makes no sense as we SEE Big Brother on a poster, and he is neither long shanked rascal or mighty of nose. It's apparently made out in the book that the Doctor has been shot (but if this was the case, why doesn't Central Records turn up information about him from his description?) or was simply never exiled to this Earth in the first place. The likeliest explanation is given by the Doctor himself - "I don't exist in your world". Perhaps this is why the console and Bessie travel with him, the only differences between the two realities being transferred between them.

As for why, perhaps the explanation can be drawn from the Doctors own conclusions at the end - that free will is not an illusion. Maybe the Doctor's journey sideways in time is a lesson of what life for the people he has come to care about would be like without his involvement. Up to now, his exile hadn't been altogether successful - he'd stopped (but not in any way destroyed) the Auton invasion, been unable to save the Silurian Race and acted too late to negotiate a peace between mankind and the un-named alien race in "The Ambassadors of Death". The Doctor was obviously in need of being shown what a difference he could make, and this is achieved by making him care for friends like Sir Keith, Sutton, Petra and even Liz (his relieved smile at seeing his assistant when he returns home - "it is Liz?" - is notable). From this point on the Doctor seems noticeably more attached and relaxed in his life on Earth (by the next story, "Terror of the Autons" he has even been socialising at the Gentleman's Club with "Tubby" Rowlands), and was therefore in a better position to help it. This can be attributed in no small part to the events of "Inferno" and his forced realisation that he could actually make a difference.