The Doctor had gotten used to the sound of his hearts drumming in his chest whenever the world was spinning out of control around him. When the alarms were going off and the bombs were about to explode and everything was just that little extra bit of exciting because he had no idea what was going to happen. It was like the orchestra building behind the apex of a film or the raging thunder and steadily increasing taps of rain before the wildest of storms.

But now it thumped out of rhythm, erratic and alternating between missed beats and extra long thuds that surged through his body, assaulted his ears, and punched and pulled at his chest. It drove him on through the bowels of the ship and begged him to stop to take a breath. It made him gasp and turn at small movements, whipping his Sonic about before shifting and hiding in small doorways tucked in corridors, or bending behind oversized black canisters, mouth agape, eyes searching.

His hearts had become the alarms threatening to explode, and they'd turned the blood coursing through his veins into ice. They'd shifted his attention to all of his other senses – to the sweat soaking his body and the tremors betraying his limbs and the ragged sound of his breath as he moved forward, further into the ship. And he could do nothing to calm them because somewhere not far away, Clara was screaming.

"Doesn't look like a friendly planet."

She'd spoken the words just moments after they'd arrived and he should have asked her why instead of smirk in her direction and rush towards the first thing that caught his attention. A motorbike. A stupid motorbike that he'd gawked over while she was peering out of the corner of her eye at the enemy. He'd told her she was being paranoid, that she was letting her Earthly assumptions of dark alleyways, dripping pipes, and a greasy smell deter her from the truth of it – it was just a junkyard. And a junkyard was exactly what they'd needed.

"Spare parts, Clara. On the cheap!"

"Doctor, I really don't like the look of this place."

She'd been right. Of course she'd been right. It was a dangerous place to be. A junkyard in the middle of space, all sorts looking for the best deals at the cheapest prices and he'd thought it'd be fun without considering that it was absolutely dangerous. And then he'd gone and walked around a corner. Just a corner. Done it a thousand times without thinking, his companion trailing behind still in awe of their surroundings, but they were supposed to keep up. They were supposed to skip behind him and ask him a foolish question he could laugh at.

"Clara?"

The sound of her voice, shrill, high pitched, and then tapering off as she lost her breath echoed down the hallway, but it was getting louder and he knew he was closing in on her. And his heartbeats were becoming just as deafening. No longer a measure of exhilaration, but of terror as he waited, knowing she'd be screaming again and when it happened, his chest shook as he moved around a corner and blasted his Sonic at a control panel that burst and triggered the doors open.

"Ah, he's come for his pet," a voice offered and the Doctor caught sight of her, lying on her back, head tilted in his direction, eyes widening as she realized who had entered.

And despite the odd angle her right leg sat at within the restraints. Despite the uneven breathing brought on by what he knew were too many electrical shocks. Despite the blood congealed on her lip and flowing slowly from her nose and ears. Despite her pain and her fear. Clara shook her head and croaked, "You run!"

The sound in his chest stopped. He might have thought he'd gone deaf because there was no sound except the roar in his mind as he moved forward. Except the roar had been real, billowing out from his mouth as he charged. The creature had been alone, and the Doctor's reaction had been unexpected – even to him. Clasping the neck that was slick with tendrils, the Doctor took him to the opposite wall as he listened to Clara moan in protest and he raised his other hand, destroying the box that sat at her left, connected to the metal bedding on which she lay by wires and clamps, with a surge of Sonic energy as the other hand squeezed.

He could hear the gasps and he could feel the flippers that slapped at him, but he only turned and clenched his jaw, waiting until the eyes bulged and the mouth hung slack and the thing that had taken her was hanging limp in his grip. And the Doctor continued to squeeze, irrationally hoping that in death it could feel his wrath, so rarely exposed, and it wasn't until he began to listen again – to hear her calling out to him – that he stepped back and the body dropped away.

Shifting, he twisted slowly, the reality of his memory not wanting to be relived, but his eyes fell on her again as she watched him and he was taken aback because the look on her face was one of sorrow. Clara looked to the thing at his feet and she closed her eyes and turned away just as he leapt to her side, fingers sliding over the restraints, receiving small residual shocks and he could see the way her body twitched as she tried to remain still. Tried to control the hiccups of gasps – all that was left of her voice between the tears and the volts that had run through her.

"Clara, I'm here, everything's fine – you're safe," he managed, unbuckling her wrists and undoing the large straps at her chest, waist, and thighs before touching her leg and listening to her cry out. "I'm going to have to set this before we can…" she was nodding before he could finish, and she grabbed hold of the very things that had held her in place, clenching her teeth and closing her eyes, waiting. "I'm so sorry," he murmured just before pressing his palms against her leg, snapping the bone back and turning away when she choked on a sob.

Glancing around, he tried to find something to help him and he found nothing, taking a breath and slipping his right arm underneath her knees before curling the other at her back, lifting her off the table and adjusting her in his arms while she buried her face in his chest. The Doctor tried to concentrate on the known then, but the reliable beating of his hearts had been muted by the ragged howling Clara was expelling as they made their way to the Tardis, each step a jolt searing through her body.

He pushed in, making his way to his bedroom and gently lying her down with a simple, "I have to get us on a course for somewhere safe; I'll be right back, Clara, right back." The promise was spoken to pale lips, pressed together in pain; the quick flaring of her small nose; the furrowed brow covered in a sheen of sweat, and the eyes that remained shut, refusing to acknowledge him.

With a quick intake of breath, he rushed back to the console and he worked the controls feverishly, his mind cataloguing the planets and the times that would be best for her injuries, and he settled on one in a fraction of a second, palming a lever roughly. He brought his hand up, seeing it trembling as he looked to the doors and then headed back to the room, this time his legs sluggish because he knew he'd have to look at her again. He'd have to see the abuse done for no reason except that she was something it had never seen before and when he reached the door, he found her staring at the ceiling, hands grasping at clumps of the fabric underneath her. Chest so still, his hearts froze in terror.

"Clara?"

She exhaled and he sighed, but then she managed to expel three words on shaky breaths that made his knees buckle as he reached for the door frame: "You… wandered… off."