Roscoe being silly.
It’s interesting that both Makoto and Sousuke withheld something from their best friends - which was information that finally brought to the surface the fact that their futures must divulge from here. Because their goals, dreams, locations, or whatever that they used to share with Haru and Rin just won’t be the same anymore.
Both Haru and Rin initially react with anger - but Rin has gotten some sense of closure after listening to Sousuke’s reasoning and having their last relay together. Haru, on the other hand, can’t even stomach the idea of Makoto leaving him on top of all the problems and uncertainty in his future he’s already dealing with, and instead of talking he just runs away and allows this problem in their relationship to continue to exist, much to Makoto’s shock and chagrin.
I just really hope they each come to realize that separating doesn’t mean their friendships have to break or lose their value, and I applaud KyoAni for all the emphasis they put on this painful part of growing up - choosing which relationships end or continue after high school is up to each person, because it’s impossible to avoid changes like these.