Dawn didn't want to listen to what Zander said, because she knew what he would ask from her. She knew what she needed to do, but she didn't want to do it.
She was selfish to watch them died and lose their beasts, but to ask her to kill Zenith, it was too much, that was something she couldn't bear.
Dawn shook her head desperately, at this point, her fear eclipsed her pain. She didn't mind to be in this pain, but she was not going to kill Zenith's life with her own hands.
She had done that once in their first lifetime, she was not going to do it again.
In this case, the story only repeated itself.
She was going to kill him. She didn't want that. The pain was too much, she couldn't breathe through the pain and Zander could see that. He knew what kind of pain that you must to endure when you have to kill your own mate, before they could kill you.