If Tatara got caught by the doves I think they will try to make armor quinques from him like Arata since his kakuja also looks like an armor. Plus he is second in command of Aogiri Tree so he has informations. Therefore they keep him alive.
Idk, Houji is the one who can get the most information from Tatara to everyone's surprise so Marude keeps sending him. Houji wearing armor made from Tatara and it makes him sick because he looks like Yan now. Houji joking about how he is finally inside Tatara after all these years and he's grateful there's a wall between them. Houji pitying Tatara for being in the most dehumanizing place because he always sees Tatara as a person. Houji refers to Tatara by his real name while the rest calls Tatara by his number. Tatara gets rehabilitated as an investigator okay i stop now