I had an incredibly weird dream the other night. I was driving with my mother and in front of us was a man on roller blades using two machine guns taped to his arms to propel himself forwards.
I was about to forget my dream all together until I started thinking if physics would allow such a thing to happen.
Similar to the way a rifle would recoil when a bullet is shot, the machine guns would recoil when the bullets are shot out of them. Normally, they are anchored to something so the recoil is hard to notice. However, the force exerted on the machine gun would then be exerted on the man, whose body would normally compensate and return the machine gun to its original position eventually. Since he is on rollerblades with little or no friction (it's my dream, I'm neglecting friction), the force would propel him forwards. And since he was firing them at a rapid rate, this would in turn propel him forwards at a decent speed.
So, while this is an entirely reckless, irresponsible and dangerous idea, it is physically possible to achieve.