It's basically what he'd already surmised. He suspects that he will need to speak to Arcee and Ultra Magnus before he can consider himself fully informed of the situation, but with just this alone it is exasperating enough. Even more so when it seems that Rodimus is already far down the path of berating himself for it - not that that actually resolves the problem.

His words are measured as he speaks, with a rigidly level tone that suggests one is controlling their temper.

"Arcee was your commanding officer, Rodimus. What you did was not only inappropriate tactics, but a frankly inexcusable level of disrespect to her as your leader and your teammate."