Judderman,
there are more ways than one to... let's says "skin a cat".
If you look very carefully you'll see the thread is named "neck break", so why would it be inappropriate to discuss that, if that's what you are implying.
Also the diving accidents probably don't do a whole lot of twisting to the heads/necks.
But, if we only discuss the twisting way of dealing with the bad guy's head, I guess you do have a point there, in that the result probably would be more dislocating than breaking (although I guess strong ligaments could rip off bony parts at their attatchment points, provided the force was great enough?).
Now I will spin off into pure speculation:
in that case to one could expect lethal outcome, due to the fact that the neck allows so much rotation between the first and second wertebrae (atlas and axis: about 90 deg total) and therefore one might imagine that's where the dislocating would occure?!? (thus damaging the spinal cord on a very dangerous level indeed)
Well... those were my thoughts, for now anyways,
arnie