The Doctor stood forlornly in the middle of the console room, feeling a desperate sense of loneliness crash over him at the utter silence inside the ship. That was another one gone, then… Another companion departing him for a normal life. A stable life. A life that he would never be able to experience…
The Doctor closed his eyes in pain, his throat clenching shut as he recalled Donna's words when he returned to pick her up from what he had thought was just an extended visit with her family for the holidays.
"Doctor, I've met somebody... A bloke. A nice one, this time. Not some loser who was just usin' me to breed creepy little spider babies."
The Doctor had forced a laugh, trying to be optimistic despite the cold weight of dread settling in the pit of his stomach. "It's not often you get to say something like that. Weeeell, not unless you're traveling around with the likes of me, I suppose."
Donna had smiled at him then, though it was obviously strained, and the Doctor knew what she was going to say before she opened her mouth. "No, I s'pose not. But, you see… That's the thing, Doctor… I can't go traveling with you anymore."
"Oh. I see." He tried to make himself sound understanding, but the words came out flat and lifeless.
"We're getting married. Shaun and me, that is."
Despite himself, the Doctor couldn't keep the stricken look off his face. "But it's only been a week!"
"Actually, it's been six months. You got it wrong again, Space Boy," she teased, though the humor didn't quite reach her eyes.
"Ah. Right…" He tried to seem light-hearted about it. No need to make her feel guilty about moving on with her life. A hand came up to rub at the back of his neck sheepishly, and a wry smirk was forced upon his lips. "For a Lord of Time, I'm a bit rubbish at being punctual…"
"More than a bit, you daft old alien," Donna interjected, nudging him lightly, apparently believing his nonchalant façade. "But you make up for it in other ways." Her eyes softened as she studied him.
"I, um…" The Doctor shifted awkwardly under her observation. "I don't suppose your new man might have any interest in traveling, as it were? The TARDIS could make you up a nice couple's suite, and I could take you both on such a honeymoon he wouldn't believe! With only a minimum of explosions, I swear."
"The thing is, Doctor, Shaun's mum is ill. The doctors say she's probably got a year left, at the most. It's one of the reasons we're getting married so soon. And, well, he needs to be here with her during all this."
The Doctor nodded matter-of-factly. "Of course. Quite right."
"But as soon as Shaun's ready, I am absolutely gonna take you up on that offer of a free honeymoon, however late it is. So don't even think about disappearin' on me, Space Boy!"
The Doctor gave a genuine smile at that, though an intense melancholy still clouded his eyes. "I wouldn't dream of it, Donna Noble."
She nodded approvingly, giving him one last sassy look before her expression softened again. "I just want you to know, these last few months have been the best of my life. I've seen and done more… lived more, than I ever imagined I could have before I met you. I can't even begin to tell you how grateful I am for that…"
They were always grateful, his companions. So very grateful for the opportunity he'd given them. For the chance to explore the galaxy and to experience things no one else could even imagine. And yet, none of it was enough to make them stay. Some got homesick and wanted to return to their old lives, others found new and exciting opportunities on other planets that enticed them to settle down and give up their nomadic existences. Some fell in love and left him to settle down and start a family. Others, still, fell in love with him and left when they realized he could not give them what they wanted. He could show them all the wonders of the universe, and in return they would help ease the deep ache of loneliness from his hearts. He grew to care for every one of them deeply, but he could not love any of them… Not like that, at least. Not until…
"Rose." The name was an agonized whisper torn from his lips as he finally gave up the battle and collapsed to his knees in tears.
The one companion who would never have left him. Not for Mickey, or her long-lost dad, or anybody in any of the worlds they had saved, or even her mother, when it came down to it. The one companion who was in it 'till the end, and she was the one who was ripped away from him. The universe was a cruel place, sometimes.
"Oh, Rose…"
Without Donna or Martha there to keep him distracted and to fill the emptiness in his life, feelings that he had been suppressing since their last meeting at Bad Wolf Bay flooded over him, leaving him collapsed on the floor of the console room with silent tears pouring down his cheeks.
He stayed that way for what felt like hours, before the overpowering crush of despair finally faded, leaving him only with a deep, aching emptiness. Finally, he managed to stand and scrub the tear-tracks from his face. He turned to the console and began to input random coordinates into the machine, taking comfort in the familiar wheeze of the TARDIS as she prepared to take him to the next adventure. Always moving on. Always running. Because it hurt too much to stand still.