You have no extensor action with your top hand to continue to pull your hands away while starting to turn the barrel. Notice the right arm in the pic and see how extensor action effects barrel turn and swing leveling. Without putting words in FFS' mouth, I believe this is what he is referring to as far as a seemless turning of the of the barrel.
As for the arrow pointing at the dude's hiney...no idea...not my pic
I have cage time on Monday and will get some vid...you are welcome to unmercilessly pick apart my swing
CP