Suwa is taking an awful lot on faith that the science teacher was right in his theory on parallel worlds. And even if Suwa in the other timeline has regrets, why should current Suwa be forced to bear the consequences? I was super relieved when this happened.
Good job. Now just do the same to Naho and Kakeru.
While they might still pull off a mushy, happy, and fairly unsatisfying ending at this point, it really feels that this episode has tipped the scales firmly toward tragedy. The only question remaining really is how much has their meddling messed with the original timeline and did any of it make any real difference?
Orange is available on Crunchyroll.