Outwest : Imagine a three legged sling holding a load. If one leg(forward) breaks the load(airframe) will shift and find a new, neutural position(pitches forward). If the force holding the three legged (now two) legged sling load up(spinning rotor head) will also find a new netural position (tilts backwards). The negative dynamic stability of this configuration is dynamicly unstable and greater and greater oscillations will likely be the result.
Like I explained previously chances are that one would have the main rotor blades strike the tail. All this would happen almost instantaniously with disastrous consequences.
On top of this you will have forces such as, added drag of the airframe, the lift of the spinning rotors and blowback of the disc adding to the already hopless equation.
Loosing a part of a blade is nothing compared to loosing one of three suspension bars (not that I would like to try loosing part of a blade . . .). My chief pilot told me a story today about when one of four suspension bars on the 206LR broke many moons ago, scary stuff . . .