These teeth marks.
10 Dance - chapter 43, part 1 summary
The day after their reunion, both Shinyas regret that they did not have the chance to spend much time together the night before. Though they communicate through texts and selfies, both are left yearning for something more.
Full summary and highlight images under the cut
This is another volume where Sugiki takes a bit of backseat (literally), but only for the first half. I love the way Inoue drew him saying the "soldier's routines" line in #25 that made him look so powerful and proud. And his pretty eyes glancing up in #26... This volume's style was unmatched.
According to the instagram MADK fanpage, the series originally had an entirely different ending. Instead of the graphic scene, we'd recieve a tearful soft goodbye between teacher and student, and then, Jonathan would say Makotos name.
If I had to guess, this last illustration in the 2016 artbook ''Heki'' is a depiction of the originally planned ending. The Donijin and Manga fundementally are not the same. So, It makes sense the ending ended would be different.