This is not a mere wire whipping, this is 100 meters of razor wire being injected into their bodies.
As for the momentum and force of the injection, if the force is great enough to push out 100 meters of wire, and then retract it in mere seconds, I think that the force behind it is quite great.
Taking a plasma shot from the outside is very different from being cut apart on a microscopic level from the inside. Think about how thin this wire is, 100 meters of it can fit lightly on the wrist of a Harlequin, it does not matter how thick or resilient the bones are of a Prmarch, this wire is so small that it can pass through just about anything.
In terms of the tabletop, it is AP- but has Rending. But the description mentions that it instantly kills the victim. It would be much too powerful to give every model in a 10 man squad instant death, so rending would have to suffice. In every case I have seen it used in the lore, it always results in an instant death.