All thoughts of helping Jon and his grandfather were gone. Karyn only wanted to make sweet love to Sarah. And Jon's grandfather could do nothing but watch them. Several times, he tried to reach to grab the stone from Sarah, but because he was a little girl, his arms weren't long enough.
Soon, though, Sarah did drop the stone. The pure ecstasy she was feeling from Karyn made her let it go. Karyn noticed it and picked it up. Jon's grandfather wondered if this was good or not. She was now Sarah's lover, so she may not do anything to harm her.
Sarah had her eyes closed, so she didn't see Karyn picking up the stone. Her eyes flew open, though, when she heard Karyn say "I wish ..."