That would be a fair reason for anyone, given the circumstances. If she was regularly hunted, Rey would be wary as well. Though it doesn't necessarily explain the prolonged silent treatment. After all, if she quickly got over the fact that a giant alien creature was being friendly with her, then was the talking part such a big leap?

...Yeah, it probably was, let's be real.

Rather than getting hung up on the little details, Rey just waves off the concern. More to herself than to Elleru.

"Well, whatever." She shrugs a bare and scarred shoulder. "You still needed to get fixed up, right? If anything, that makes this easier now."

Rey's no veterinarian. She wouldn't know the first thing about telling whether an animal was in pain if it can't communicate what's wrong to her.