So I thought this episode—wrapping up a two-parter about the Doctor (David Tennant) turning himself into a human so as to avoid some aliens who are hunting him and losing himself in early 1900s England—wasn’t going to get any worse after Tennant, having regained his memory and alien… superpowers (sure, okay), asks his human love interest, Jessica Hynes, who he no longer can feel the same way about, if she’d like to join him on the TARDIS.
In order to have this moment, the episode needs to ignore the following. First, Hynes is an early 20th century racist White woman who has been overtly racist to Freema Agyeman. We don’t get to see Tennant and Agyeman reunite, not really, even though she’s spent two episodes catering to his similarly racist White 20th century man when he didn’t have his memory back and had to keep him (and his lady) alive while he was ready to surrender the secrets of the universe to the bad guys. The human Tennant. Because he was a dipstick.
Second, Hynes has already rejected him in his alien capacity. Not just because Tennant no longer loves her—it was a fairly chemistry-absent love in the first place—but also because we’ve done the “the Doctor’s a violent, cruel guy” actually reveal in this episode. The Doctor is willing to do the violence so others don’t have to… which even figures in with the pre-WWI boys school militarization thing—macho imperial British jingoism in 2007—there’s a lot wrong with this episode and the previous one, it’s just not worth going through all the things. Even if they are fascinatingly dated for their time period.
Third, there’s no impression Tennant has checked with Agyeman about Hynes joining them. Like. Two episodes about Tennant being apathetic to the companion and he’s just as apathetic as before. Even though he remembers everything from the human phase, including Agyeman confessing her love. So he’s intentionally cruel.
But fourth, it doesn’t matter because the episode manages to get worse with the Saving Private Ryan postscript.
It’s a big episode full of bad ideas. Agyeman ends up as dissed a companion as Billie Piper and, even more striking, Tennant’s stopped being enough of a draw on his own.