Wow, that was.... expected.
We already knew from ch 161 Yuko simply loved Esemori and that he wouldn't have the balls to kick Uryu, Yuko, on the contrary, would have the nerve to get rid of the things that were between her and Nozoe. The only thing that adds up is that Shino'oka had a heavy hand onto Yuko and Akira's fallout happening by feeding up Esemori's schizoph... Don Qvixote complex for the sake of turning him into a novelist.
Such a serious sin, however, made Reiji finally see that light he was rejecting. And the reason that he could see it it's because she also was a person, not a people of light. Shino'oka admitting her sin, and recognizing her inner darkness may be the final factor for Reiji to make a decision. As people can bright that intensely, said bright may hide a hidden pitch black darkness. And viceversa. A deep abyss may hold a faint spark inside that is only waiting to be ignited.
Next week, the end of Shounen no Abyss begins, according to the Young Jump magazine, even though the official account and Ryou already announced the final act the days around new year.