At the sound of Optimus' slowed speech Magnus' expression dropped, legitimately concerned for his commander. They'd been in dire straights before, but it had been a very long time since he had last seen Optimus this frayed, this physically and mentally drained. He had to get Optimus to the medibay before he crashed.

"With all due respect, sir, it would be irresponsible for you to pursue any sort of labor at this point, physical or otherwise. The best way to help the others now is to ensure Ratchet is able to complete his work as quickly and efficiently as possible. I'm certain he would agree that your health is of greater importance than whatever tasks you have determined require immediate attention." If anyone could get Optimus to actually sit down and rest it would be the medic, and Magnus was perfectly willing to guilt Optimus to the medibay if that's what it took.