At that crutial point she could do two things, escape or she could work on her inner emotion and stop herself from being in fear so that whatever that creature was would stop feeding from her fear to grow more powerful.
She closed her eyes and worked on her rationality repeating to herself internally she didn't have to fear that huge snake in front of her, she was with John and she was just as strong as that creature if not even more.
Roselyn kept trying to lead in her mind those thoughts even tho it was very difficult to coinvice herself when usually she was the first person who doubted her own capabilities. But she had to be confident for once. They were in that drastical situation because of her and it was her duty to get them out of that trouble.
