Home.
That sound. That sound was the very fabric of time and space ripping and breaking, the sound of a TARDIS engine, the sound of time travel.
"Oh, blast..." mumbled the Doctor realising that he mistakenly put salt in his tea, rather than sugar. Unfortunately for him, he hadn't had enough time to tell Charley before she started coughing spluttering all over the TARDIS console. "... Sorry about that." He laughed. But before Charley had time to recover, he ran towards the doors to the rest of the TARDIS.
The Edwardian girl was furious. "Come back!" she commanded. She ran after him.
The sound of the engine was pulsing and invading the console room, the large central wooden console glowed with all different collections of kaleidoscopic buttons, incompliant switches, stiff levers and incomprehensible screens that were displaying all kinds of befuddling riff-raff. The glow increased and decreased as the Time Column rose and fell. The Time Column, a central spire of glass, which contained integral parts of the extraordinary engine that lay below it.
The TARDIS console room had undergone a radical change within the last few years. Before, it had been a wondrous white, clean and sterile, with the occasional grey wall, here or there. The walls, covered in circular structures dominated all the walls in the whole ship, everywhere you looked, not a single bare wall in sight.
But things had changed - the TARDIS interior had metamorphosed into a dazzling cathedral-like structure. Everything was either made of wood, stone, or metal. The TARDIS had changed to make the Doctor feel more at home. His thoughts had been transfixed on his home planet, where he had "grown up", having visiting there days before his last regeneration. He had left terribly homesick.
But the one thing that the Doctor hadn't realised was that Gallifrey wasn't his home, neither was Polarfrey or Earth for that matter. Not one single planet in the whole, wide, awesome universe was his home. Whenever he wasn't enthralled in one of his many heroic, thrilling – and sometimes silly – adventures, he was in the TARDIS.
He was Home.