[...] I went into the photobooth because it was like a cupboard and it felt safer and I could look out through the curtain. (211.50)
Once again, Christopher confines himself into a small space, and that makes him then feel safe. At the same time, though, it affords him the freedom to peek out through the curtain, and to watch how other people use the subway ticket machine. So, it sounds as though he benefits from finding freedom within confinement.