To be honest, I don't think the author is particularly clever. Sorry for saying this. I didn't mean to look down on someone. So, I think Shinobu just slept straight through until nightfall while Sakura was xxx with the fucboy in his room (not at a hotel) even though the abrupt jump from day to night by just a single panel felt a bit rushed. I don't want to dash the hopes of the optimists out there. After all, Chapter 131 did move along quite hurriedly.
However, Volume 14 is set to conclude at Chapter 136 or 137. If the series is indeed ending, this might explain why the author rushed to deliver such a terrible conclusion : she was dissatisfied with being ordered to end the story, so she spitefully crafted a disastrous ending by destroying the characters and the entire narrative. And because she lacked professionalism, only acted on impulse, she ultimately sabotaged her own future. It's sad if it's like that.