“I have no other customers.”
Clearly Mei is also in the store but either the store owner doesn’t see her as she is a ghost or she chooses not to acknowledged her presence as Mei is some kind of demon. It’s already been proven she has some sort of supernatural element about her as she can disappear when she wants to.
The other thing I noticed this episode which applies to the last episode as well is that nobody except Kōichi was interacted with Mei. It raises the same question as before. Can nobody see her or do they choose to ignore her.
They find it awkward every time Kōichi mentions Mei in conversation or when somebody else does. What I find more ineresting is the group of three students that met Kōichi at the hospital the redhair girl who is probably a tsudere seemed angry at something that happened during her one day absence. I think this might have something to do with the othr girl in the group letting Kōichi go to the roof and talk with Mei.
The dolls appeared a lot too and you ave to think they symbolize something but it remains unclear at this point. Mei allowed Kōichi to look at her drawing in the library which was some sort of wingless which could very well symbolize something to do with heaven and spirits but I don’t want to think about it too much.
If someone is going to die it will be the nurse otherwise I suspect that Mei will reveal some details to Kōichi along her eye and the three students will become more agitated.