You were trying to play a prank on Akutagawa. You and Atsushi hid in one stall in the men’s bathroom, waiting for him to walking to jumpscare him, but he never came. Chuuya and Dazai walking in, the both yelled at each other, while you were still recording to scare Akutagawa. Then you and Atsushi hear them both go into a bathroom stall together, and you both hold your breath in shock, the noises or gulping from Dazai.