I also really like the way they're doing his rehabilitation, he genuinely had no idea of anything beyond his pessimistic and honestly pathetic goals so when Yu beats him and he's left with only the promise he made he works on following up on it. Even accepting the cops are gonna beat the shit out of him and wanting to return to prison after being kidnapped by Shou.
Adachi just feels real to me, he's a character I feel can genuinely exist in our world.