I’m curious that rather than the actual ideal taste of her victim, what she’s vying for, rather, is the resulting reactions a human that struggled and found hope to live only to have it ripped apart once again in front of her.
I imagine what she’s actually waiting for is Hinako to struggle and fight helplessly to live as she wants to see Hinako’s despair return to her eyes once again after finally finding a reason to live. If she’s truly as cruel as she’s being made out to be, it must be that Shiori wants to torture Hinako by leading her to a false and brief hope that she’ll end up destroying herself to see the hope fade from Hinako’s eyes as Shiori kills her.