Author's note: Despite the mushiness of this title, I'm not a Clara/11 shipper. It's totally cool if you see it that way though.
Clara Oswald never really believed in reincarnation, but after deciding to leap into the Doctor's time-stream, she'd have to rethink her stance on it. She knew it would be a gutsy move (reckless, he would've pointed out), though she was emboldened by the fact that technically she'd already done it.
In spite of that, he still wouldn't allow her to risk herself. Even though he'd been writhing on the TARDIS floor, his lanky frame jerking in every possible direction, he was still imploring her to think of another way. But he was dying! She couldn't just stand there and do nothing, not when she had the opportunity to correct the timeline.
River, like the Doctor, knew what Clara had intended to do, and so urged her to reconsider. But River also didn't attempt to stop her; both women knew that this was the only way. Instead, she gave the almost-newly christened Impossible Girl a sad smile and a nod.
Clara took slow, deliberate steps, cautiously approaching the time-stream. It was pulsating wildly, glowing a violent blood-red, with tints of black marring its edges. The sight reminded her of an open wound, she thought, tasting bile in her throat. How could someone inflict this much suffering on another person?
"No...please!" the Doctor wheezed, the words sounding harsh and grating to her ears.
Hang on, Doctor. Just hang on. Clara thought desperately, trying to stave off her own panic. She only had one shot at getting this right, and she wanted it done as quickly and painlessly as possible. "If this works-" she whispered, keeping her gaze on the rapidly darkening time-stream. Her voice became stronger, more confident. "If this works, get out of here as fast as you can." She paused, mulling over her next few words. "And spare me a thought now and then." she added as an afterthought.
"No...Clara!" he yelled thickly, sobbing.
Please, Doctor. she thought, shutting her eyes. Don't make this harder for me. She took a deep, shaky breath, bravely facing the time-stream. "In fact, you know what?" She turned to look at him, eyes shining with fiery determination. "Run. Run, you clever boy...and remember me."
"NO! CLARA!" But her fate was sealed with one graceful leap.
She didn't know where she was or where she was going. All she remembered was that she was supposed to save the Doctor. Save him from a fate that hasn't happened yet, is happening right now, and has happened several times over. She'd do anything to keep her Chin Boy safe, so long as he continued to live.
She was there when he first began his journey, and she'll stay by his side when he decides to end it.