Whatever he was expecting, this is decidedly not it. He backs off a few steps as the man starts to change into a wolf, eyes darting from him to the woman still in the car.

"Can you stop it?" He asks her, because judging by her expression he doesn't think she (if she really is the cause of the other man's sudden transformation) did it on purpose. So it's a distinct possibility she can't control whatever this is-

Hopefully the werewolf? shifter? can at least control his wolfish instincts, or they're going to have a much bigger problem on their hands than the involuntary transformation itself. He subtly prepares to cast a Steadfast Ward, just to be on the safe side.

It doesn't even occur to him that whatever forced the other man's transformation might affect his own magic.