Tarn turns to stare at Ratchet as he dodges the swing of his arm. The hit was clearly aimed for his t-cog; the stare turns into a glare in seconds.

"No need to be stupid, Ratchet. I would think that you would have better sense than that. Disappointing."

He's honestly trying to avoid a fight for once. Megatron is still in the back of his mind, and Tarn is not particularly keen on losing the alliance that he was carefully constructing. If the Autobot is trying to harm him, however, he can supposes he can claim self defense...

He moves to drive his elbow into Ratchet's face, grabbing the his wrist to keep him from pulling away.