It's all I can do to sit still while the bands play. I can’t believe Mirror Boy was in the system. I don’t know if he was when he died or not. (The Ghost Files, by Apryl Baker)
Who's "thinking" here is a teenager who can see ghosts. She and the kid she's talking about are foster kids. Considering one of the comments, it's probably a metaphor. But I can't quite grasp the meaning.