"Hey, that's a great idea." Or, well, it may not be a great idea, but it's a Magnus idea. He's clearly already pretty thrilled at the idea of fighting the junior guards single handed.

"Actually, I find the best way to learn is through instinct, you know, realizing you had it in you all along. So what if..." This is already getting worse the longer he pauses to flesh out this idea in his head. "What if you don't tell them I'll be helping train. Instead, you send them out on patrol, and I'll jump them, and they'll learn how to fight and how to be vigilant to danger. And when they survive, then you can be hiding nearby and tell them they passed the test! So I don't get arrested."