Whatever reaction Optimus had been expecting it wasn't that, and he takes another half step back in surprise. Of course he's never known a time without Autobots and Decepticons, or Shockwave's relationship to his Optimus, or any context for the outrage. But this wasn't the kind of outburst he would expect from a double agent that managed to make it onto the Autobot Council undetected, he was willing to take the chance Shockwave was telling the truth.

"Alright. Sorry, I guess." He reaches up slowly in a placating gesture, "Sorry. This whole ordeal is a lot to get used to. In my universe we, uh, only just found out about Shockwave infiltrating the Autobots, so I guess you could say it's just a little unnerving on top of everything else going on here. I didn't mean any offence."

He put his arms down, looking sincere if confused. "If you're not an Autobot or Decepticon, whose side are you on?"