I cannot tell if this was blurred on purpose, I think you were going for motion. At any rate, I think the way it was excecuted takes away from the pic. Maybe a multiple exposure would work better.
I know what you were trying, but it doesn't work because it looks like they are moving backwards. You needed to jerk the camera in the other direction but also need a plain background to hide the deception.
Nice idea, and nice attempt at execution. Just trailing camera motion blur would be better -- flash, then move camera toward the left so that blur is all toward the right. A tripod with panning might help. Also adjust levels to recover more detail in the foreground figure.