In Beyond the Ordinary, I think Beive has already experienced that. Her biggest fear was to loose her dad, which stated in the first chapter that it already happened.
She lost everything and is so bitter and mad at this, but she keeps it to herself and try not to loose it.
When she begins to see these magical, mystical creatures, she's all "Oh, I've lost it. I wonder what might happen next". She's surprisingly cool about it.
I do believe her biggest fear is to be turned back into a half-bird again.
In Pierre's case, it would be to loose his sister. He doesn't see her often as they live in different towns, but he kinda sees her as a role model and he looks up to her a lot!