After beating the crap out of a metal pole (and scaring off a couple dudes who were going to chat her up) A frustrated Ao retires to her room to study. The subject: Takumi, of course! Specifically, why, despite all of the compromising times he could have made a move on her, including when they were alone in the ocean.
After imagining their roles (and genders) reversed, and breaking her mechanical pencil agonizing over it, she gets a text from Takumi inviting her to watch his soccer game. Then it dawns on her: he lacks the stamina to do what she wants him to do so she can reject him!
She accepts his invitation, and prepares a magnificent multi-level bento packed with aphrodisiacs, including oysters, truffles, and eels. The plan is, she’ll feed him the stuff that will turn him into a savage beast that can’t keep his hands off her, and she’ll reject him fair and square, leaving her free to study again.
Of course, it doesn’t go as planned. While Takumi loses the game, his spirits are immediately raised when he sees Ao’s bento. Little do either of them know that Ao’s pops spiked the eel with one of his patented “energy” elixirs.
As a result, Takumi starts feeling all hot and bothered, and before she knows it, he’s on top of her. But he still manages to hold back, telling her he’s suddenly not himself today and that she should leave before he does something. That’s when Ao asks why he won’t do it.
The answer is instructive: because he values her more than his own desires. Ao turns that around on herself: if her desire is to get into a good university, feeling the way she feels about Takumi would naturally place him above those desires. That’s just how love works; it can literally sweep you away from the best-laid plans to just…getting laid.
Unable to accept such an outcome, no matter how happy it might make her, Ao decides to leave and tells Takumi not to ask her out anymore. The more time she spends with him, the more she’ll value him over studying. Of course, she’s oversimplifying things, and there’s such a thing as work-life balance. If she just lays out her concerns, there’s no reason to think he can’t keep his distance until she’s in a good school, or assist with her studying in some way.