Four rested against the side of the TARDIS, gathering his energy again. He’d been trying to recover from the regeneration cycles by walking around London, a little bit at a time. The TARDIS had decided she’d follow him whenever he went on a walk, just in case his energy suddenly gave out and he collapsed again. It was reassuring that she cared about him so much.
He closed his eyes for a moment, waiting for a few minutes until he could resume his walk.