Though any sensible person would understand that this isn't necessarily a personal brush-off, Cade is... rarely sensible, and his face falls a little when the Seeker dismisses him.
"Right, ser," he says quickly, awkwardly, ducking his head in a small, respectful nod as he steps away, "I'll just... um. Be here if you need me." In the meantime, removing himself from Reed's presence seems like the thing to do.