Kaidan picks up on the approach of someone he can't hear. He's paying attention to his surroundings, no matter what anyone could say. He's on his feet before the shadow makes itself known and he knows his fingers are cracking a sharp blue, if the pain in his temple means anything.

It cuts out when he sees who is approaching. It's an old squadmate. One of Shepard's best. "Garrus? What are you doing here?" He's the last person Kaidan ever planned to see. If Garrus is here, though, where's Shepard?