Physically, if she'd wanted to get out, she probably could have, but it would've involved hurting Castle. Emotionally, she had already broken when she allowed him to pick her up and physically carry her out. She wasn't going to hurt him and emotionally she had already given into being removed from the fight even if she hadn't physically moved. She was faced with the shock that the cop she had trusted and who had trained her was involved in her mother's death (albeit as somewhat of a footnote) and I don't think she was physically committed to risking her life to save his at that point.

I had no problem with it.