That's what I had in mind as I was watching the video : one needs to be taught the right thing to do then practice, practice, practice. Anxiety is rooted in the conscious (or unconscious) lack of confidence of being able to do the right thing in a stressful situation, hence the need to be taught the right procedure and practice.
I am very green and because of that, I regularly take my mask off during my quarry dives to practice. I am having fun adding a bit more difficulties as I go (put it back on with only one hand, keeping trim and buoyancy, doing it within 3 feet, etc). I am looking forward to take the rescue class to get confronted with difficult situations to test myself and learn.