I have to wonder what does Tomikawa's eyes getting filled in mean, since Hiiragi's are normally in that state. Even now that she feels partially safe with Tomikawa.
Does that mean that she's not just taking all this as something to fill time and enjoy herself, but as something she can take seriously? Was she taking her friendship with Tomikawa as something less important than people which would give her affection or something?
Or is it just the more straight-forward answer of "she's turning to obsessing over Hiiragi"?