On finals at 300ft, what manouver is likely to push the rotor through the tail boom?
From previous accident reports involving all sorts of helicopters:
Sudden control input trying to evade a bird. Pilot losing consciousness. Passenger interfering with controls. Control linkage failure. Blade failure. Pilot distracted by trying to close door, causing a low-g situation and roll. Low RPM blade stall for different reasons..... etc etc.