[If this is an ayakashi, then that might be why Mari has been having so much trouble lately. Sure, she probably would've prayed anyway -- what student doesn't, when exams are looming? -- but ayakashi make everything worse.]

Don't worry about a thing, Mari. Just keep on studying. It's going to be okay.

[Elsa waits to make sure Mari is still focused on her work, then nods at Hakkai. All at once, she's aware of the details of the room, and she's watching them for changes, looking for anything that's not the same as when they came in.]

I haven't seen anything hovering around any of the students. That so-called trick of the light you saw -- was it moving in a specific direction?

[Maybe there are no ayakashi here, but they could be nearby.]