She had been tense as she walked behind Taiki, not wanting a dangerous element at her back, but she needed to be between Taiki and harm, between the train and the danger. She was as aware of him walking behind her as she could be, so when he stopped, she stopped right after. She listened to what he said. Two things hitting her at once.

She could not and would not make that promise. She owed it to Axel to be the one to let him know he was here, and wanted to be there protect him if it went wrong.

But the other thing...

She turned to face him. "Why do you keep saying that?" she challenged. Even her? What was that supposed to mean? Was this more about her being a failure? Being broken? Was this because she had the Keyblade and e wanted to use it like Xemnas wanted to use it? Was it something else?