*Snape is good at hiding his emotions, so to Wesley, he gives a bland expression. He knows he can't take Wesley in a fair fight, so he inwardly seethes at this unexpected and unwanted show of bravado. He lets Wesley pass, his blank face showing no hint of his true emotions. But once Wesley has passed, Snape briefly, just long enough for Barty and Reg to see, makes a horrible, very dangerous face behind his back. Still, he follows wordlessly, biding his time.*