"I put my heart and soul into my work, and have lost my mind in the process." – Vincent Van Gogh
It was still a habit, you know. He still imagined her everywhere. If he had been in his younger years, closer to his early hundreds, he would surely have had someone diagnose him legally insane. But still, a flash of her hair around the corner kept him running when his hearts were ready to burst and his new companions were kilometers behind him. She would be standing right next to an ancient stone pillar, her brown, vivacious eyes scanning the architecture and the carvings, asking him questions. That is what prompted him to explain all sorts of facts and figures to his friends walking right next to him. Or they would be seconds from death and she would run right towards that big button he needed to press. Then he would have to run over there and beat her to pressing it first. She would sit right next to him when he was lost in thought in the consol room, smiling reassuringly and listening to his every word. After a while, when they were talking amongst each other one afternoon, he realized that he never over exaggerated her capabilities. She never mindlessly recited facts and figures aloud, like a manifestation of his own self-conscious. He was always able to do the logic himself. And no one could tell that he was seeing someone that wasn't there. As a game he would test them, say something aloud to thin air, and they would shoot him a look but keep going anyway. And she saw that he would do that and she would get angry, in his head they would argue, and she would storm off. She only returned when he was alone again, whispering in his ear to let him know she was back. She humbled him when he was getting to be too self-centered. She would hug someone who needed the compassion. She would fall asleep with him, lying so close but never touching, and she was the first thing he saw waking up the next morning. The poetry of the universe sounded that much more beautiful to him when she read it aloud in the TARDIS library. A plate right next to his own would be stacked with the same amount of food he had been given if he was attending a feast, and his napkin would remain suspiciously clean even if hers was appropriately dirty when they couldn't eat any more. A finger nail painted with bright colors pointing downwards alerted him when his shoelaces became untied. A beg for mercy would save someone's life who probably didn't deserve it. Tissue boxes were kicked in his direction when he sobbed.
One thing that kept reminding him that it all was in his head was the fact that they never held hands, never embraced. It would hit him like a ton of bricks when he touched something from the real world, how solid it felt to the touch. And then her hand would ghost over it, and not even a dust particle would stir. Nothing could be done. He never for one moment considered leaving her behind. He was addicted to her. It was all he could do to stop himself from reaching out and making that first move, that first touch. And oh, the words. The words that she spoke. "Don't worry about me. I'm alive." "Do more, be more!" "We can do this, together." "Can I try?"
And then he reached out to her. The first time he tried, she disappeared altogether, reappearing when he least expected her. The second time he unthinkingly clasped her hand in the midst of a battlefield. And though his encircled hers, there was no warmth or the pressure from contact.
Until finally, his mind was lost. The third time, she was solid.