He shouldn't be surprised by the silence, but it catches him off guard. Gripping the railings that lead up to the console, he hangs his head a moment, simply listening, but nothing sounds familiar anymore and for a moment he tells himself it's just the memories he's lost, the ones he jettisoned to keep all of his memories of her. But he knows the truth – without Clara, the Tardis sounds empty.
It feels empty.
Raising his head, he stares around at the blueness of it all, more blue than he's ever seen it and he understands that the machine is feeling her loss as well. Can hear it in the wheezes and moans she gives as she struggles to keep them afloat in the universe, as if the effort of continuing were too much and it angers him. Moving over the metal, he slams the gears and toggles the thrusters and he screams.
"Come on you old cow!"
It roars from somewhere inside in response and he grips the edges of the console, feeling his eyes burning because he knows that he has to keep going, even without her there. Old fool, he tells himself, you've travelled without her before. Hundreds of years before and hundreds of years during, in the gaps between meetings you've moved over the universe without the faintest hint of a frown. Except it wasn't the same because he knew that phone would never ring again with her voice on the other side of the line asking him where he was, asking him for a favor, asking him to show up at her doorstep because it's Wednesday and he promised.
"For a man with a time machine," she'd told him once, "You're never very punctual."
The words bring a crooked smile to his thin lips as he remembers the way he'd poked her nose, watching her frown in amusement as he reminded, "It's a time machine, not a clock."
She'd merely shrugged, skipping past him towards the console to give her a small pet and an appreciative smile, as though she were sharing a joke. Now he could only look at the small notes she'd left about, little reminders to herself about how to fly her – because she'd been taught, he knew – he used her notes when he forgot himself, until he could manage just fine… but he left them there, finger lightly tipping up one yellow paper before tracing over the letters.
"You should choose a new companion," her voice tells him sternly and he turns. For a moment his heart races because she's standing a few feet away, hands in the pockets of her skirt, smug grin on her face, deep dimple begging to be caressed – like always.
But it's simply a hologram. It's the Tardis using her to tell him… what she would.
"Doctor, you should choose a new companion."
He shakes his head and raises a hand in her direction, "How do I replace you?"
"It's never a replacement, thought I made that clear." Her head cocks slightly, memory replaying, "I'm not a bargain basement stand-in for someone else. I'm not going to compete with a ghost."
The Doctor can feel the warmth in his eyes and when he blinks, the tears roll over his cheeks. She'd always been so concerned with being a ghost and in a lot of ways, he'd treated her as one – never allowing himself to get close enough to understand she was real until she was gone. Turning to the door, he listens as she repeatedly clears her throat, and when he turns, he shakes his head and laughs.
He finally understands, and now she is just a ghost.
Just a whisper of a memory played through a computer trying to ease his pain with advice he's heard from far too many companions when they depart – please, Doctor, don't be alone. With a smile, he taps against the controls and watches the hologram round the console to lean at his side and he absently raises a hand, dropping his head when it falls through her and hits a lever roughly and she scoffs.
"Not very clever of you."
"Who asked you, huh?" He sniffles.
She smirks, "I've stored the recordings of Clara Oswald, complete with personality analysis into your database, should you be needing them, Doctor."
"Thank you," he sighs before smiling, "Could I ask a favor?"
"Yes, Doctor," the hologram responds.
Furrowing his brow, he asked, "She sang sometimes – couldn't use the iPlayer to save her life – and she made me play her music, but, I can't recall what it is. Do you?"
The Clara beside him smiled brightly before giggling to herself and the Tardis came alive with a soft strumming of strings and a soothing voice that made him sigh and smile. Mumford and Sons, he knew immediately; silly folk music that always made her happy. She'd fallen asleep to this song once, he remembered suddenly, sitting in the library looking over a book from a time and a place that she shouldn't have looked at. Nodding to the echo of her, quietly singing along next to him, he straightened, sniffing roughly before correcting the settings on the board in front of him.
He smiled when she tilted her head and began singing louder, hands coming up to sway with her head before she began dancing about and for a little while he could pretend everything was as it should be. He steered the Tardis through the time vortex, for a time not settling on a destination – simply drifting to enjoy the hologram entertaining him.
And the ghosts that we knew will flicker from view
And we'll live a long life