Nera jumped in the first opportunity that she could get to run away from the place that had been confined her. She used her power to conceal her presence so those magic users couldn't find her, but then once she already stepped out of the castle, she crippled her own ability to used her divine power, in order for Rei not to be able to track her anymore.
She harmed herself, she put her life in danger because she destroyed her own power. Of course, Nera could heal it back, but she would think about that later. Her only priority right now was to get away from this continent as soon as possible.
Thankfully, she managed to get to the harbor in time and jumped to the ship, in which took her to Karam continent.
Nera fell sick during this journey, because she destroyed her own divine power, but she still refused to restore it. She hated her power, because Rei loved it so much. She knew what happened, she knew his obsession toward Na, the first Serafim and how he saw her as her.