My only part in this is keeping you from doing something idiotic and risking yourself unnecessarily. Not to mention the mission.

[ Why that matters to him, of course, is the key -- it's definitely partly himself, seeing a glimpse of Byerly and how much he cares for Sonia has him want to work to help him. But mostly it's for her sake, and maybe a little for Miles', too. Sonia clearly cared for Byerly a great deal, and Miles called him a friend he'd trust with his life. That's good enough for Wash. ]

I don't give a damn about your duty or honor or whatever it is that keeps you so intent on your death for the sake of her protection. All I know is the objective, like I keep fucking saying. All three of you. Safe.

I'll do what it takes to get it. Meddling included.