Rereading, I don't think I ever realized what a blatant out fishwoman gave herself here. She only promised to devour "this you", in a conversation where they were already talking about the different versions of Hinako being different people and Hinako was being all "the me you met back then is already dead!". I'd bet anything the conclusion is going to be "but Shiori, you already *did* devour the sad, depressed, lifeless version of myself I was back then".