Akira just tried to imagine how they would apologize.
I got confused too. There was no indicator that it was just an imagination lol.
There is an indicator but it's very subtle you barely notice. Other authors make the page black or round edge panels to indicate imagination/dreams. In this case, the imagination panels are thinner than regular panels, like grey lines instead of black. You can see them on pages 4 & 5 of chapter 17.
The grayed background is within the panel, instead of outside. No wonder it's not noticeable. Unlike in Korean webtoons the black is the entire back ground or in JP manga where there's clear indicator before the panel.
i dont get it, didn't Kazuma come with Akira to apologize the first time? That time when Akira ran? Whyre they acting like its the first time Nanao's seeing Kazuma since then