Kōyō, after hearing the news of Dazai leaving, decides to go check on her younger subordinate, Chuuya, knowing how close they were. She hasn't seen him all day so it's fair for her to assume that he's having a bit of a hiding away depressive episode

Kōyō walks towards Chuuya's office, knocking gently on the door as to not startle him

"Chuuya? Are you in there?"

Kōyō calls out, trying to be gentle with her voice but she needs to make the sure the small redheaded boy actually hears her