The last thing Hot Rod had expected as he entered Optimus Prime's office was to have Grimlock be sent flying back into him as Optimus Prime stood smugly over the fallen Dinobot. (and the nearly crushed former leader under him)
He'd heard about Grimlock having problems with Prime in his early days on-line. But the Dinobot had mellowed as his personality came together. While still ornery and aggressive he wasn't as hostile to other Autobots, and had actually seemed to consider himself Rodimus Prime's bodyguard. So the idea of Grimlock attacking Optimus was virtually unthinkable, however the idea of Optimus Prime physically assaulting one of his troops without physical provocation was completely so.
As his processors struggled to solve the mystery he noticed an orange sphere in Prime's hands, and Grimlock gathered his wits enough to speak.
"Me Grimlock call charging!"