Mig talked about getting the bat on plane as quickly as possible when he did this demonstration. Do this move at full speed, with a wood bat, and you get the barrel turning rearward behind the shoulder and then arcing into the swing plane, transitioning from forearm axle to palm-up/palm-down. One of the problems with slo-mo demos is that the rotational forces of a heavy bat being swung at full speed change things dramatically.