One day he found her huddled in the arboretum, arms encircling her knees, and tears running down her face. He crouched down beside her, one hand resting tentatively on her back.
"Clara? What is it? What's wrong?"
She didn't reply, lost in reverie.
The Doctor settled himself on the grass. slipping his arms around her. "Hey…what is it? Were you too tired to make it back to your room?"
She finally shook her head. "No. Not that. I…I was…remembering."
He sighed, and rested his head against hers. "What? Or should I say, when?"
She sniffled a bit, and swiped at the tears on her cheeks with the backs of her hands. "That Christmas, in London, when we were in the TARDIS, and you gave me the key. I started to cry, and said I didn't know why…but I did. I was crying because you finally saw me, and when you gave me that key, I thought…well, I thought that maybe it was over…that maybe I wouldn't have to die anymore. And then…well, you know what happened next…"
A solid brick of guilt rose up in the Doctor's throat, threatening to choke him. He swallowed harshly, feeling as though he were inhaling broken glass. "I do know. Of all the mistakes I've ever made, that…not being close enough, or quick enough, or whatever enough that I needed to be to save you, that is one of the ones I regret the most."
"I know. I know you would have saved me if you possibly could. And I know now that it needed to happen that way for the rest of the timeline to play out. Only just…don't beat yourself up about it, all right? Because, ultimately, it was my choice…and I'm okay with that."
The Doctor wasn't entirely sure that he was okay with it, but he had no words to refute her, so he just tightened his arms around her, and prayed to anyone who might be listening for the strength to get them both through this.
