I have a feeling that he suffered an accidental death on the first loop, but girl didn't know if it was suicide or not. On the second loop (when story starts) he experiences the same thing at the end of the story, where someone will eventually die, and he decides that if someone must go, might as well be himself.
On third loop and on this chapter we start to understand the girl's attempts to correct his regret, but never once attempted to correct hers. Even if they survive, by playing the observer role the whole time, Chihiro still intend to confess her feelings, even though she was somewhat absent from his inner circle for the whole time? What if he turns her down? WIll she regret anything else?
Now i wonder if Class prez confess to him during the trip and they decide to go out, would that correct the loop?
Chihiro mentioned that Guy was very agressive on the last loop, but she should take that advice on herself and be more close to him, share more experiences with him, be more agressive and then confess. I think something might change then, because she wouldn't have more regrets about high school, just like everyone else.
Really nice story, enjoyable to read. Tnx for translating!