Yeah I was pretty amazed when I saw the video myself. The age of modern technology does have it's advantages, way back when we just had to guess at what was happening but now we can see it with the advancement of slo mo cameras to slow things down for us.
When I first saw the video I was only using one string nock for shooting 2 fingers under and I did get better arrow flight than when I was using split, but after watching the video I went outside and stuck another nock on my string just below the arrow nock leaving about a 1/16th clearance under the nock so it wouldn't pinch and my groups tightened up immediately. Been using the same set up ever since.