I'm shocked and amazed that he hasn't, as yet, shot himself with that Glock.
In the videos, you see why ... he teaches positioning the index finger so as the weapon comes out of the holster the trigger finger rides high against the slide. To learn this, the finger ‘learns’ the feel of the belt line prior to the weapon coming out.
It is fun and not difficult to do fast. I have done this multiple times every time I take conceal carry night drill. As soon as the gun clears the holster, tuck the elbow into your side and pivot gun. 3 shots into target in front, 2 steps back, full aiming extension and Mozambique to second target to right. And I do it with a GLOCK 26.