"It's happening," the Doctor told Clara, gritting his teeth through the pain, "and when it does, you can't be anywhere near me. It'll hurt you."
Clara nodded with a concerned frown on her face. "Are you going to be okay?"
The Doctor forced a grin—crooked, just like his bow tie—and said, "Of course. Just a new me, but you've seen that before." He suddenly gasped and clutched one of his hearts. "Oh, there goes lefty! You have to get out, now!"
Clara spared him one last look before running out the TARDIS door. She started to close it behind her, but hesitated. She finally settled on leaving it cracked, just enough so she could hear him.
"You're not real, you know," she eventually heard him mumble between ragged breaths. "You're an illusion. Maybe something the TARDIS put up to comfort me, or maybe I'm just going even more mad before I leave."
There was no answer, but the Doctor chuckled. "It's sort of…ugh…fitting, you know? The first face this face saw, now the last. But really, I just wanted you to know… I love you. Ever since I crashed into your garden, you were etched on my hearts. We had a good run, didn't we?
"Well," he sighed, "I guess this is it." A small groan escaped his lips and his breaths sounded like a marathon runner's. "Goodbye, my Amelia." Clara could almost hear the smile in his voice. "Geronimo."
Clara gave in to her curiosity and peeked in just in time to see a flicker of red hair before gold shimmering light filled the room. She quickly pulled her head out of the doorway and closed the door.
"Well, come on, Clara," she heard a strange voice call from within a moment later. "Let's see what you think. "
It was months later before she gathered up the courage to ask him about it. "So, Doctor," she said hesitantly. "Who's Amelia?" The name seemed familiar to her somehow, but she couldn't quite place it.
The Doctor looked up from the console, eyes widened in surprise. "How do you know about Amy?"
"I heard you talking to her, before you regenerated."
His look of surprise turned into one of gentle nostalgia. "A friend of mine from a long time ago. She traveled with me for a while. You met her when you were a Dalek. She," he told Clara with a smile. "was actually River's mum."
"Hm," Clara considered. "Kinky."
"Well, you said you loved her."
"No, no, no," he said with a grimace. "She was my best friend. It wasn't like that. It was like… well, I met her when she was seven, and I watched her grow up literally overnight. She married Rory—"
"Oh, Nina!" Clara remembered.
"—and they gave me River. Amy was a Scottish girl in an English village. Ginger," he said with a frown, "so she has that on me." He stopped for a moment, hand on his Adam's apple with a soft smile. Yes, that must be it. "She must be where I got this from," he said, feeling the roll of the r's in his throat.