Those doors aren't supposed to be soundproof at all XDD
In Japan, those sliding doors are not actually supposed to be soundproof. They're used as a divider for multiple rooms in traditional stay houses. And you can tell it's traditional, because of the tatami mats on the floor. The sliding door is called "Shoji" in Japan though.
that's exactly what i said their (dorm) rooms might be soundproof (tho we're also not sure) but those sliding doors in that resting house is definitely not how come no one heard them LMAOAOAOAOAOAO
LMAO YAOI LOGICCC
and it doesn't even makes sense i understand that no one might've heard them going at it in their room cuz it may be sound proof but AT THE BEACH?? AND AT THE REST HOUSE WITH SLIDING DOORS IDK,,, i just stayed for the memes and the smex tbh lmaoo