As Ben waited for his opponent to strike he sized him up, butterfly knife, meaning that he would likely be good with his hands, the way he was not letting down his guard showed he was at least not an idiot in the ways of Combat.
As he gracefully struck at Ben he smirked, shifting his weight to the right and side-stepping the blow, as he passed Ben the officer made a punching motion of his knife,hand, not aiming directly at the man, but slightly to the side so that the blade has a chance to slice him, this was a mere probe of his defenses, to see what he can do.