We have dissected this video for years at training courses. Old school lineman rescue. Take a wrap around the pole and over the insulator, tie a bowline to the victim, cut his lanyard/buckstrap, and control his descent using the friction from the wrap on the pole.
Goob was in a hurry and you can see that he grabbed the lead of the lowering line rather than the fall, so he was holding all of the weight of the dummy, which pulled him forward, which in turn pulled him off his hooks, and...
Speed should never be a factor in AR. No other rescue group does this, just arborists. If you ever get a chance to watch EMTs or First Responders you'll see that they respond quickly but never rush into a scene with the thought of get this guy to the hospital quick.