This evening while doing my monthly battery testing I was able to "accidentally" recreate the falling out of the sky "dead" issue. I flew several different locations today and came home with some partially discharged batteries. The last day of the month I log all of my batteries and deep discharge any that are around the 20 cycle mark (20, 40, 60, 80 etc). I had a battery that was at 47% and I wanted to run it down to less than 10% to initiate the Recalibration function of the Smart Battery. I was watching the actual battery statistics while hovering just above eye level. I wanted to see just how much difference putting a heavy load on this battery would do so I (don't repeat this at home it's not safe) took hold of the landing skid and applied more throttle. The motors revved hard but the battery indicator was barely showing red on one cell so I increased the throttle more. Tx immediately indicated "Critically Low Voltage" (still showing 45% capacity but voltage was red on every cell). Within about 2 seconds the aircraft completely powered down and had I not been holding the landing skid it would have tumbled to the ground. So if you are trying to get a few more minutes by flying with a partially charge pack realize you could very easily cause a complete power-down. Air temp was roughly 54degs so it was not a cold battery issue at all. Good luck and fly safe.