
Now I suppose there's the simple suggestion that you leave "Letters of Transit" to the very end of the season, but that would have rung a little anticlimactic. If you think about it, the last four episode of the season really act as a four-part season finale, but in this case the first of those four episodes told us where Season 5 will take us. Does that obliterate any tension from the remaining three episodes? In a manner, yes. We know who lives to see the year 2036, and that makes it rather impossible for any of them to die. But there's also an inevitability to the rest of proceedings. "World's Apart" was such a pedal-to-the-floor episode as it tried to veer in the opposite direction of catastrophe, only to reach the conclusion that closing the door between universes was inevitable.