[ It's easy enough for Derek to keep pace, although he does look a slightly concerned about Stiles' breathing pattern. When he speaks up again he keeps his tone calm, clearly he's just hit a nerve with the Scott talk. ]

Slow down. Whether he cares or not isn't the problem. If you keep it a secret and he finds out, what's going to happen? What'll happen if he finds out that I knew about all of this before him? We're going to need his co-operation.

[ If he comes back. ]