Ah yes, that is a great title indeed. Taking adult responsibility is something good protagonists should always do.
I must say though, what a lucky coincidental mistake he made...Opening the door to the room next door. While most would probably catch some dude fapping, Hentai has blessed our protagonist with a lovely girl masturbating right then and there.
Great ending though. She doesn't really need to apologise, if anything, he should take responsibility for what he did...And I'm sure he will.
Opinions may vary as to whether "Vanilla" tag might apply to this story, but Cuvie in "god of vanilla" mode has depicted the Perfect Fated Encounter. Don't Waste The Opportunity, Male-Protag-kun, unless you then surrender your "Man" card.