Rodimus watches with a vague expression of interest, shifting uncomfortably now and then while Ratchet works. But at least the arm is salvageable.

"Well first I ended up here, and then I got kicked in the face by Brainstorm. But only after Ironhide nearly hugged me to death." Look at how helpful he's being, Ratchet. He's edging into sulking territory but first he must be as obtuse as possible. Only a little on purpose. "And then I corrected Megatron on the matter of ranks and Tarn took it badly."

So that explains the arm and the giant dent in the shape of a hand on his other shoulder.