Shori eating a bunch of food seems suspicious. I may be putting too much focus on it but it seems it's her way to sustain herself a little so she doesn't feel as hungry for Hinako, CLEARLY indicating her restrain is being eroded little by little.
And Miko's description of Japanese mermaids made me laugh, I want Hinako touching Shiori's horribly grotesque form.
I'm guessing there are more beach women ocoming? because of the hands you can see under the water. It'll be interesting if it was a different creature.