This is really interesting insight actually. Seems like their relationship is a lot more in context timeline wise in the novel.
Idk it's sort of made me reflect on the challenges of adapting things to visual media. In written work there's so much reliance on us being directly told what we need to move the plot along - e.g., "I looked at his face, his eyes seemed kind".
But in visual form, the artist simply shows that emotion in their expression, but how that translates to us as readers, or how we infer it's meaningful depends on their talent.
Since there's just a lot of sex scenes, it's hard to tell whether MC is distressed or not. The artist doesn't really differentiate and make it seem like Shinje is particularly kind or nice.
the reason why shinje and yugeon are acting romantic now is because the novel built them up to be romantic this entire time, to the point that from this point onward there is absolutely no way to continue the story without including the fact that yugeon is in love with shinje. however, for whatever reason, the manhwa has adapted the story while cutting a LOT of scenes from the novel that show that steady build up of romance (imo, the artist has a different favorite ML and also really liked drawing the rape scenes… they could have been cut, most of them weren’t that long in the novel but whatever). just know that shinje no longer wants to die because he wants yugeon to live and he wants to live alongside him. yugeon is heavily crushing on shinje. shinje is the only one out of the others that treats him gently (yes, even while being harsh other times—recall yugeon’s first time. shinje took time to prep him for it and everything, the scene dragging out much longer than the novel).