[ Suddenly he actually doesn't care that much about what Rin thinks about his and Atsumu's not-relationship. Because there's something much more important to address. ]

Why d'you know -- never mind. [ Ugh, whatever. His actual point: ] Don't tell Gray what's going on here on this side. With Silco being a hissy little bitch at me.

[ Presumably, Rin can connect the dots here for why Silco is being such a colossal shitheel at him. ]