Might I suggest that if the rotor had stopped it would nevertheless have quite a bit of drag (the instant some airflow gets hold of it it starts turning which creates lift which creates drag which ...) and thus an aerodynamically induced rotor stop at a few hundred feet would result in a braked fall with a force vector that tended to keep the aircraft upright - sort of like a drogue. So damned bad luck could have pointed the aircraft at the pub with nothing to do but wait and turn stuff off for four or five terrible seconds.
None of which suggests any reason why the rotor stopped or why the whole sequence started.
Iain