The pace of the first six episodes of this story has been relatively slow and drawn out (to its credit), but the final installment moves along at a breakneck speed. Things really only start to go off the rails for the Daleks in the last five minutes. (Apologies to those who have never seen this story yet, as spoilers are to follow. But then, if you've been reading this blog this far, you probably already know I don't really avoid them, anyway.)
The final battle is monumental, but I'm surprised that it really happens at all. In Episode Six, the Human Factor Daleks are recalled to Skaro, along with the rest of the Daleks. However, instead of being isolated for study or incarceration (the Human Factor Daleks were only really created, as the Emperor Dalek states, to determine what the Dalek Factor is), they are allowed to roam free and mingle with the other Daleks. Much panic ensues when one is discovered to be on the loose, but it never needed to get that far. Why did the Daleks pay so little attention to the Human Factor Daleks once they got back to Skaro?
In doing so, the Daleks just did themselves in. The Human Factor Daleks start asking questions, then start to revert back to their one basic instinct - kill. The ensuing war (which starts and escalates very quickly) seems to be only between the Black Daleks and any Daleks infected with the Human Factor (thanks to the Doctor's sabotage of the Daleks' transformation arch).
It's fun to think of how this story plays into what we know of established Dalek history today. Because of The Doctor's actions, the Daleks are destroyed. A couple hundred years in his own future, he would have the chance to destroy them again in Genesis of the Daleks, but would hesitate. Does he reconsider then because of the genocide The Doctor inflicts in this story? Does The Evil of the Daleks take place, as some fan commentators would be keen to suggest, in the far future, and is, indeed, "the final end" of the Dalek race? Once the events of Genesis of the Daleks occur, does Evil even exist in the new timeline? Books could be written speculating this kind of stuff.
My primary impression while watching this story, though, was the weight of expectation. The Evil of the Daleks is often lauded as one of the all time classics in Doctor Who, and it is difficult to watch it without having its lofty status staring you in the face. As I said earlier, this was my first experience with a missing adventure, having listened to it years before I came across any other missing adventures, so i already knew what to expect. I fully expected Evil to supplant The Power of the Daleks as my vote for the best Troughton story, if not the best Dalek story ever, but it did not. Evil is good, don't get me wrong, but I think most of its reputation is derived from the explosive finale. Pound for pound, I am still quite firmly in the Power camp, although to have two such strong Dalek serials in the same season is worthy of note, as their adventures would seldom reach the heights of this quality ever again.