Derek stiffens when she whispers, because she's making any sound at all. "What are you doing?" he hisses at her, looking around quickly. Normally, Derek is all for going full force right into the eye of the storm, but that's when he's a werewolf. Right now, he's a human and he's never been all that great a fighter. At least with his werewolf abilities, he's faster and stronger and he can heal pretty quickly. As a human, he's no good at fighting and he doesn't have any of the extras that might balance his lack of skill enough to make him passable.

"So shouldn't we go the other way?" he asks in that same whisper.

Another sound behind him has Derek moving again, whirling in place and falling into a fight stance because at least he's got that down. There's nothing there. Derek's heart is racing, thumping so hard in his chest that he feels like it's going to beat right out of him. His adrenaline is pumping so hard it feels like he's trembling. "Jesus, what the hell, what the hell, what the hell...?" he whispers more to himself than to Buffy.