Position #2 is called 'Keystone' and the kinesthetics of the powition are important. If you read the 'Kinesthetic Procedure' post this will be familiar.
You are in the address stance. Hold a club/stick/pipe with your lead hand in a golf grip with the back of your lead hand facing away from you and the object parallel to the target line. Grab the object about 12" away from your lead hand with your trail hand with the palm facing outward. Your trail hand is the 'Claw'. Now pulling up with your trail hand so that your trail elbow is driving toward your belly button, apply the maximum pressure you can without loosening your lead hand grip or allowing your lead wrist to be anything other than flat of slightly convex. You are forcing maximum wrist cock and the most acute lead arm/shaft angle possible with a good lead hand grip.
This is the position and 'kinesthetic dynamic' you take to the top and the one you bring back down.
The left knee buckles toward the target-line, there is a slight bend in both knees and then in its proper sequence occurs the VERTICAL DROP of the KEYSTONE position, that is the relationship of the arms to the club as was achieved in Position Two. At the top of the backswing the Golfer's hands were a few inches higher than the Golfer's head, and when our player has completed Position Four, making the MASTER MOVEMENT into the MASTER POSITION his hands have now been lowered to a point at least three inches lower than his right shoulder. NOTE: There has been positively no un-cocking of the wrists, but preferably a little more cocking of the wrists.
The movement described results in a drop of the arms well below Hogan's plane with minimal shoulder rotation and slightly more pelvis rotation. This position is QUITE dramatic and account for the unique look of Sergio's swing. In the
Hogan clip this movement can bee seen very clearly when in the same frame at the top you can see Hogan's lead knee move toward the target, his trail elbow appear by his trail side and his hands deop while the club head stays at about the same level (increasing wrist cock.
At the end of this motion your trail elbow is as low as it will go so you are on the lowest plane to the ball possible before rotation (ala Dunigan) without easing wrist cock.
The illustrative pictures of Hogan and Player in the book are quite dramatic as well. They are from the rear parallel to the target line and show clearly that both dropped from the top to a position with the the shaft horizontal and nearly parallel to the target line but below shoulder height! At this point both still had their shoulders very closed to the target (only about haldway to parallel). It is also clear in these pictures that bot were the opposite of a 'trail arm thrust'. In fact both clearly have more bending at the trail elbow between top of swing and the dropped position.
Peter