Tiffaney was trying not to imagine the worst outcomes, thinking that it was to late. Her kidnappers forcing themselves on her or worse, making her cook for them!
I wonder what's for dinner…
That wasn't important but as she was sitting with nothing else to do, it was her brain trying to protect itself from her mounting worry and anxiety. Instead, it took a considerable amount of mental focus to redirect her thoughts to something useful.
Looking around she could see a few others in the hall who received letters looking pale and uncertain. Realizing this wasn't just her gave additional considerations for herself.
Elizabeth never would leave the academy and there was no one outside it to lure her out. Outsiders were not impossible but inviting a group to kidnap so many different people would be significantly difficult and costly for such a risk. If that holds true, then the most likely culprit would be other students.
