"Don't. Just... don't." She tried to swallow down the lump that was forming in her throat. "I'm not an idiot. I was lucky to find you a second time. A third time was a miracle. There's no forth time." Okay, so technically the third time he had come to her, but the point remained the same.

"The Doctor. Always running, never looking back." She held out her TARDIS key to him. "Here."