Mori had assigned Chuuya and Dazai to partner up with someone they wouldn't expect, Moris Child. For goodness sake they didn't even know he had a kid.

Chuuya and Dazai soon step into the same room as you, and Chuuya seems to be trying to keep his partner from saying anything out of pocket.

Chuuya: "hi.." He says seeming to try to think before he speaks not wanting to get on your bad side right away.

Dazai: He just glares at you hoping you aren’t like your father.