He always felt like he had no time to do anything. Constantly feeling rushed, breathless out-of-date. That's what usually happens when you find yourself protector of a planet, a universe. You get stressed. And it's not a good stress. That feeling only intensified when he met Rose, and the moment he saw her what he really saw was how quickly she was running out of time. And the only thing he had time to do was take her hand and urge her to run. And after that, all he could see was how fleeting her life would be, even if, for a human, she lived long- all he could see was a time she wouldn't be there to steady him. She had managed to turn a monster into a man, and for that he would always love her.
Eventually he settled into a pattern, teaching her as she taught him, and he worried less and less about losing her, about running out of time. At least until the Beast prophesied that she would die in battle, and though he told himself and even her lies, he had a feeling they both knew the truth. Rose, he felt sure, could feel it in her bones. And he didn't have time to get used to it before it happened, no time.
He had no time to grab her hand and keep her close when they opened the void, no time to warn her not to pull the lever, no time to save her. He only had enough time to see it happening and to feel his hearts breaking as she was torn away from him, screaming her name, reaching out. He had enough time to place his hand against the wall, his cheek, and imagine her on the other side, waiting for him to get her out.
But there was no time. He had no time to save Rose, and he never forgave himself for that. He made time to say goodbye by killing someone's world, someone's universe, someone's sun and stars and sky. It seemed fitting that the only way for him to say goodbye was to make more trouble for him. He had two minutes to tell her how brilliant and beautiful and perfect she was, and how much he loved her, and how sorry and angry he was that he couldn't be with her.
But there was no time. Two minutes was too little time. He was a coward; two minutes wasn't long enough to muster up the courage, staring into her eyes, feeling pathetic and small and insignificant compared to her. The worst was that he could not hold her while she cried, and knowing that she cried that way because of him. It was his fault, after all, that he'd let them get so close. It would've been easier, he speculated, if he and she hadn't let themselves believe that this time would never come. He could see that she wanted, needed him to say it before he left forever.
But there was no time. She said it, gasped it out, tears streaming down her face, though he knew she was trying to be brave. It scared him to know that the thought of losing him was so terrible to her- "I love you," and she managed to muster a sort of smile. He swallowed, feeling his hearts jump to his throat and his palms start to sweat, even though they were on opposite sides of the Void. The best he could think of, the best he could force his choked-up mouth and brain to even consider replying, was a throaty, "Quite right," which he immediately hated and knew sounded pompous. "And, I suppose," he paused then, forcing himself to curl at least one corner of her mouth, be strong for Rose- "Here's my last chance to say it…" He saw her pupils dilate in anticipation, but with a sinking feeling he realized he had very little time. "Rose Tyler," and then her image faded. It was a moment before he realized she couldn't see or hear him anymore, and he opened his mouth to finish his sentence before he realized and closed his eyes in anguish.
There was no time. He let the tears run down his cheeks, but then he had to move on. That was the way he worked, the way he had promised Rose he would move on. He would never forget her, and he would always speak of her.
i"There's a girl- a brilliant girl, miles and years and ages away, separated by a Void so deep you can't even feel your heart beating there- and she has saved the world so many times that nobody can count. She has turned monsters into men, stopped a world war, fixed the future, taken out a werewolf, tilted on the axis of an impossible planet and sailed through a black hole. There is a girl so fantastic that there are planets and moons and stars named after her, and beings millions of light-years away sing songs of her. There is a girl so dangerous that an institute was created to keep her away from her own country. There is a girl so beautiful, so pure, that she managed to capture a Time-lord's heart and turn it from stone to something that could love again. There is a girl that I would have shown everything, all that the world is and it's ours for a moment and then gone- but there was no time. Running out of time isn't about not having any time. Running out of time is about having all the time in the world and letting it get away. Running out of time is using the time you have the wrong way. Running out of time is never telling someone how much you love them until it's too late. And now my time- our time- is up."/i