Well no, because box cutters are inanimate, but I'll tell ya what, in the spirit of education, give me a box cutter, Ill give you 15 feet and you can come at me with your "fury", all 200lbs of it.
BTW, I'm 230lbs, I do know Kung Fu (Ju Jitsu, TKD, Kenpo, Judo etc...). Care to come get some and prove a point? We'll use a sharpie marker for my knife, you can come at me full force using only your physical body.
You've seen too many Die Hard movies, or atleast you believe too much of what you see. If you get into a knife fight, you will be injured, you may even die...ever been in a knife fight? I have, it aint pretty. I got stabbed next to my nuggets, changed my attitude real fast.
Not trying to tell you I'm tougher than you, only smarter, maybe more experienced. Be smart man, you only get one life, make it count.