I notice several things as I watch this. First, the action is completed before the right arm begins any pulling motion that will follow. Second, the hips move completely to the pole (in the direction of the runway). And third, the shoulders are driven down toward the box, and they end up completely under his inverted body. This video provides visual representation of some of the text that has been written on this subject.
If you haven't already tried doing this move on a bar, give it a try sometime. Then you will understand why I call this a power move.

View this video by clicking here. Credit for the original video is given to stabhochsprung.com