Very sad, and all the more so when it involoves someone trying to save/protect others.
Without wishing to go down the speculative line that so many of these threads do, I can't believe for one second that a high side failure could cause the blades to shed (as suggested above) and am amazed it has been suggested. For a start, the power turbine/generator turbine would almost certainly burst first and secondly, when main blades are shed they tend to fly a lot further than 340 ft; more like half a mile.