Rose saw the hellhounds and saw the battle that took place. Erik was ready to protect her, but she wasn't ready for that. All the screaming and fighting really freaked her out. She was wearing her mother's hairclip that gave her control over people, but she wasn't sure it worked on hellhounds. In the end some newcomer banished the remaining hounds and everything was fine. You could say.
From the shock, Rose fell on her knees. It wasn't like her to be this weak, but you could say only now she truely realized how much danger is involved with being a demigod. She took a deep breath and tried to regain her posture. I'm fine, its only because im inexperianced. I'll learn.