She just couldn't fight anymore.
As her Keyblade cut through another Heartless, Aqua felt her vision blur. More and more of them had been appearing each day, as if sensing her flagging spirits. Constant attacks had kept her on her toes; she hadn't slept for days. Or was it days? Without a source of light, her internal clock had lost track a long time ago. She noted with a bitter laugh that it was hard to keep track of time when you were fighting two Darksides at once.
And that's when it happened.
A swing of her weapon made sloppy by fatigue missed the swinging Neoshadow by a couple of inches, a pair of claws tore into her stomach, reopening several previously-afflicted wounds. Blood seeped all over her clothes.
"C-C-Cure." She didn't have enough energy for Cura or Curaga. As it was, that spell had completely exhausted her magic supply. It was enough to stop the bleeding, but the pain still persisted. To make matters worse,the Heartless chose that moment to intensify their attack, driven into a frenzy by the sight of her blood. Blows rained down on her from all sides as she finally fell to the ground. It was all over.
Ven...Terra...I'm sorry. I guess I won't be making it back at all.
The last thing she saw before her eyes closed was a narrow beam of pure light.
...
...
...
Wait Light?
"SALVATION!"
The shock of hearing another's voice made her eyes snap open. No longer seeing her as a threat, the Heartless that hadn't been incinerated by the spell had turned their attention to this newcomer, who cut through them with a determination she wished she had. Behind him, the light was still there, and it had expanded into a giant door. After the boy had dispatched the last enemy, he handed her an elixir that she gratefully chugged down. Her vitality restored, she gazed at the face of her rescuer.
"That face...Ven?" No it wasn't him. The hair was darker and in a different style, but the resemblance was uncanny.
"Nope, my name's Sora." The boy flashed a giant grin that reminded Aqua of when Ventus had gotten her and Terra those passes to Disney Town. Tears came to her eyes. "Why don't we get you out of here?" The door opened, allowing the two of them to pass through to the Mysterious Tower. The morning sun bathed the two of them in its warmth. Fresh air filled her lungs; the ground beneath her was soft and smooth to her touch. It was all real. It wasn't just a dream. After so long, she was finally free.
She was well and truly weeping now; her tears spilling into the grass. The boy looked at her in concern. "Are you all right."
After several moments of sweet relief, she wiped her tears and stood up, new energy and resolved filling her whole body. She would save them. She didn't care how long it took or what stood in her way. "I'm all right. Thank you so much."
She wouldn't stop fighting until her friends were safe again.