The Ark

As the Doctor, Steven and Dodo go on their merry way at the end of "The Ark", conspicuous by its absence is any sincere statement of apology or even acknowledgement that the whole thing has actually been all the Doctor's fault. By rights, "The Ark" should change the Doctors entire outlook on the consequences of his wanderings, and evoke the same kind of moralistic resolution of self approvement that the Sixth Doctor later makes in "Slipback" and "The Two Doctors".

Put simply, the Doctor bringing a sneezing Dodo into contact with mankind's descendents indirectly leads to their suppression at the hands of the Monoids, who then inherit humankind's right to exist, at least until they are later overthrown. Interestingly, it's not 100% clear that the germ the Doctor brought to the Ark and later thought he'd immunised the humans against is responsible for the reversal of dominant species by the time they reach Refusis. Yet the very fact the TARDIS immediately jumps forward in to this particular, critical time in the lives of the people it has just left behind suggests that in some way the Doctor is being shown the results of his interference. Fictionally, the TARDIS is taking him forwards to see the consequences of his actions (or else the second landing rests on an almost absurd probability!) and factually, the two parts of "The Ark" only make sense if they represent cause and effect respectively.

An adventure where the Doctor does little more than fix the fallout of his own tampering is by no means unique to "The Ark". "The Chase" is the first story to be "about" the Doctor, rather than having him intervene to save another planet or its people; thus any deaths that occur on and en route to Mechanus are indirectly his fault on the grounds that they might never have occurred if he hadn't antagonised the Daleks in the first place. In fact it could be argued that on many occasions when the Doctor faces an old foe (and as we know there were certain times in the series history when he couldn't so much as pop to the shops without bumping into one) the blame for the casualties that occur throughout the adventure lies at his feet. In "Remembrance" he quips that he doesn't want to "lumber Earth with a load of desperate Daleks" but this pang of responsibility for his own battles wasn't in evidence when the Great Intelligence took over London to set a trap for him, or when his feud with The Master resulted in umpteen invasions of Earth.

Come to think of it, the Master is an interesting case. It's interesting that the series implies time and again that the Doctors exile to Earth at the end of "The War Games" was timed to coincide with a flurry of alien invasions which he was put there to help avert. And yet in "Terror of the Autons" it's the Doctors very presence on Earth which draws the Master there and results in most of the later assaults on the planet! Could the Time Lords not have lifted the Doctors exile after "Inferno", and thus prevented the planet from being in any subsequent danger in the first place? "The Face of Evil" is another odd Doctor Who story, again completely concerned with the Doctor clearing up after himself. And by the time we get to the late eighties, he is actively creating situations for himself to resolve.

So there are many different ways the threat in a Doctor Who story can be established. There are the stories where the Doctor would have helped more by simply not turning up, the stories where the threat is arguably only in existence as a result of an earlier victory and the stories which blatantly showcase that all actions have consequences. We should be thankful that the series at least has a conscience, and acknowledges that sometimes things aren't better after the Doctors involvement. As in real life, even well intentioned deeds may ultimately come at a price.