Mickey and Rose were asleep, in separate quarters. The Doctor hadn’t expressed any opinion about where Mickey should sleep, but after he came aboard, Rose ushered him to his own room and settled him in. The Doctor didn’t blame them or their inferior human physiology for needing rest, not after what they’d all been through today.

The Doctor didn’t mind being alone, either. He had work to do. Ensconced in the middle of the TARDIS, in a room the ship had created especially for his tinkering, his attention was entirely focused on the workbench in front of him. His lithe frame was hunched over a sprawling pile of gears, tubes, and circuitry. His Time Lord brain recalled each of these pieces with perfect clarity — he’d used them before, for construction of the Mark III version.

And as he soniced each component into place, he thought of those who had known each of K-9’s various incarnations: of Leela, Romana, Adric, and of course Sarah Jane. Sarah Jane, beautiful and passionate and still very much herself.

Older. Closer to death. With a sharp inhale, the Doctor shook his head, pushing the grim thought to the far reaches of his mind. Pushing away the accompanying whispers about Rose and her mortality.

Instead he focused on this K-9 Mark IV and the delight he expected on Sarah Jane’s face when she realized her companion wasn’t gone. The Doctor shoved his sonic screwdriver into the pile of circuitry for the dozenth time and murmured, “It’s all right, old friend. You’re going to be all right.”

(Source: dammitzayn, via flapperorslapper)