“Who is he?” asks Bill as they head away from the barn, following along behind the man who’s been Bill’s closest friend for the past ten years. A man she’s known far longer than the Doctor, at this point.
The Doctor’s eyes move wistfully over the stranger – not Razor, she won’t call him Razor – in front of them. “A very old friend of mine.”
“A friend of yours?”
He looks over at her, hesitating a little. “Do you remember when I told you Missy used to be a man?”
Bill nods, and the Doctor sort of swallows and shifts his gaze back to the stranger. There’s a short pause where he doesn’t say anything else, and the answer comes to Bill in a sudden rush. She stops walking.
The Doctor stops too, staring at the ground and scuffing one of his boots against the grass. “That’s Missy.”
It leaves Bill reeling. The man that she lived with for ten whole years is actually Missy? The man who made her laugh whenever she felt sad or lonely, who cooked her breakfast every morning and lent her clothes to wear when she had none, and – in the really early days, when Bill had been too weak to raise her arms above her head – even helped her change into those clothes, helped her arrange them loosely over her unnatural looking chest-piece to disguise its shape. Ten years of friendship and trust and after all of that it turns out he was someone else all along – he was Missy all along.
Bill feels sick. She feels sick right down to the very core of her being.
And to make things worse, she isn’t even sure which betrayal she's most upset about: her closest friend of ten years turning out to be a monster, or her closest friend turning out to be more the Doctor’s than hers.
“All that time he was just using me to get at you,” Bill realises, and a horrible bitter feeling shoots through her. Why does everything seem to revolve around the Doctor? It’s Bill’s life – why can’t things be about her, for once?
“I’m sorry, Bill,” says the Doctor, and his voice sounds small. Bill doesn’t think she’s ever heard him make a heartfelt apology before. “It’s all my fault. Everything that’s happened to you. I’m sorry I asked you to come here.”
She doesn’t offer him any words of comfort, because she’s not sure she’s ready to forgive him. Instead, she offers him the same words she uttered all those years ago, back when he first asked. “Yeah. You’re still a bloody idiot, you know that?”
This time there’s no levity in his tone when he agrees. Bill sighs, watching him stare at his boots for a little while, before linking her arm gently through his and tugging him along after Missy’s past self. They walk in silence for a while, until Bill notices that the Doctor’s movements are awkward and uneven.
“What happened to your leg?”
“Oh, this?” he says, tapping his hand against it with a self-deprecating smile. “A cyberman got me.”
It takes a moment for that to sink in, but once it does a leaden weight of dread takes root in the bottom of Bill’s stomach, and she stops dead.
“Was is me?” she whispers.
The Doctor looks over at her with an unbearable kind of sympathy. “No. No, Bill. It was you who saved me.”
She doesn’t remember that.
“I’m fine,” he continues. “Please, put it out of your mind. It doesn’t hurt that much, anyway.”
He’s lying. Bill can always tell when he’s lying. “I can’t put it out of my mind. I still care about you even when I’m angry.”
The Doctor lets out a long breath at that, full of emotion and unspoken words. A moment later he’s stepping forward and wrapping his arms around her in a hug. Bill buries her face in his shoulder and tries not to cling too tightly. The seconds tick by while they stand together like that, and Bill takes comfort in the calming rhythm of his twin hearts beating steadily against her chest. Eventually the Doctor pulls back.
“That must have been a bit odd for you,” she says self-consciously. “Hugging me when I look like something else.”
“Oh, Bill,” says the Doctor, and his eyes crease like he’s trying to smile but he just ends up looking sad. “It doesn’t matter how you look. You could never be anything else – not to me.”
Later, the two of them stand side by side in front of a ramshackle house as Nardole leads a small band of humans to safety. This is a good way to die, Bill thinks. Very action hero.
And more than that, she’s not doing it alone.
“What you said the other day,” says the Doctor. “About not wanting to live if you can’t be you.”
“I think… I think I’m starting to feel like that too.”
Bill frowns. “Well, it was never likely for you, was it? You’re not a cyberman.”
“No. Just a Timelord,” he murmurs, with a sad little smile. “A very, very old Timelord, who’s lived for far too long.”
An ominous rumble works its way slowly around the landscape, and the ground tremors a little. The Doctor pays it no notice.
“I hoped it might be different, this time around,” he continues thoughtfully. “Quiet, maybe. Something I could accept. But change is so exhausting. It took me ages last time, to piece together who I was again.”
He tilts his head up towards the sky and closes his eyes. “I don’t want to change again, Bill.”
Bill swallows. There’s something undeniably mournful in his tone – something she doesn’t quite understand.
“Doctor,” she says softly. “I don’t have a bloody clue what you’re on about.”
He laughs at that – a full, happy laugh that nevertheless does nothing to disguise the redness around his eyes when he opens them again. “Neither do I, most of the time.”
Before Bill knows what she’s doing or even why she’s doing it, she reaches out and pulls him forwards. The Doctor falls gracelessly into her hug, gripping her shoulders and holding on tightly.
“Do not go gentle into that good night,” he says quietly, against her ear.
“Dylan Thomas,” Bill whispers.
He pulls back just enough to look at her and there’s a smile on his face – the warm, tender smile that he reserves just for her. “Did I ever tell you that you’re an awesome student?”
“Nope,” Bill says, with a smile of her own. “But it’s okay – I knew that anyway.”