This wasn't supposed to happen.
While yes, it is inappropriate to get "unreasonably" angry near the Armed Detective Agency members, but could you really blame him? Dazai teasing Kunikida, Atsushi talking to Fukuzawa, all the other members chatting away in bliss... He could hear all of it. The conversations weren't just morphed into a talking blur either. He could distinctively hear every single word very clearly all at the same time. Any normal human being would probably have a meltdown, Ranpo wasn't an exception.
Panicking, he tried to get away from the noise. Somewhere more quiet. He felt a couple hands reach to pull him back from his desk, but he couldn't be bothered to listen to them. He knows he should've approached the situation more calmly. More "mature", as most people would've said it.
Ranpo finally grasped his headphones, putting it on his head quickly. The loudness finally died down, however he isn't quite calm yet. He just needs some alone time, or comfort. As long as he isn't bombarded with someone like Dazai again.