Even preoccupied as he is with reaching Scott, Derek doesn't get far before realizing he's got a tail. The guy's good, he'd probably admit if forced, but there's no substitution for werewolf hearing.

He's not surprised, truth be told. If Stiles has been blabbing about Derek being a... well.

He's not surprised.

Since he's going to have more than enough to deal with when he gets home, he lopes down a short side street and turns right and right again, only then pulling up to listen and wait.