A different reading of Twelve’s "love confession” in The Girl Who Died
Ashildr is dead. The Doctor is guilt-ridden. Clara tries to console him. He says he’s sick of losing people. And he turns to Clara and talks about her eyes, her kindness, her “never giving up to anger”* and then he shocks us by basically telling her he’s in love with her:
One day, the memory of that will hurt so much that I won’t be able to breathe, and I’ll do what I always do. I’ll get in my box and I’ll run and I’ll run, in case all the pain ever catches up. And every place I go, it will be there.
Here’s something about this statement that gets overlooked, and I confess it never really registered at the time, or for a long time after.
We know now, of course, that Clara, not too many episodes after this, dies and the Doctor nearly tears down time to bring her back to life. So his statement here makes sense in retrospect as both foreshadowing and an indication (alongside “Before the Flood” which was a dry run for “Hell Bent”) that he’s willing to go to lengths to keep her safe.
But he’s not talking about Clara dying here. Yes, he stated his concern about her safety earlier in the episode when he invoked “duty of care” - that specific point, therefore, has already been made, so he’s not repeating it here. He’s not assuming that Clara will die. He’s assuming that Clara will, someday, simply leave him - like all of his companions eventually do (and he’s not talking about her staying with him and dying of old age, either; he knows companions never stay with him forever). But, instead of moving on has he’d always done before - even through his two-season-long mope after losing Rose, he still moved on and didn’t let it consume him - he is predicting that this companion, should she ever leave him (giving up travelling, finding another Danny, whatever) would leave him incapable of functioning and cause him to run away from the pain. What pain is he talking about here? The pain of her death? No, because he doesn’t know she’s going to die. He honestly cannot cope with the idea of Clara leaving him for any reason. (Hence the memory wipe being, realistically, the only option.) People who are BFFs don’t talk in these terms. There are really only two categories for this: family (see his response to losing Amy and Rory) and people in love.
So we tend to look at this scene with the benefit of knowing what comes later and we look upon it as foreshadowing the grief the raven ultimately brings. But, taken on its own, this is a totally unambiguous moment showing the Doctor, his emotions bubbling to the surface over sacrificing Ashildr, letting his guard down and laying his cards on the table for Clara. The fact Clara appears either unwilling or unable to register what this man has just said - which supports the theory that, while she was in love with him all along, Clara never realized that Twelve was actually in love with her too until Hell Bent’s “duty of care” moment - is one of the tragedies of Series 9.
* This is how I’ve always heard that line, and it makes more sense than the Doctor talking about her anger as being something he’d remember.