One thing I do in the simulator, is to enter in a "1 G" 90º bank (!) to initiate the descent, with the idea of getting off the the airway traffic below, and also to avoid getting the passengers to the ceiling of the cabin
Having conducted one emergency descent for real, I found no need to bank and turn in order to momentarily increase the aircraft rate of descent. The danger of a wing-over type turn is in IMC where large bank angles can quickly get out of hand. A gentle easing forward into the initial dive attitude is almost imperceptable to the passengers if the pilot (human or automatic) flies smoothly. Turning to clear an air route is another thing altogether and of course requires fast evalulation of new MORA. Passengers hitting the ceiling because of negative G in a dive is surely caused by only the grossest of poor flying skill by the pilot.