Heh,
This is one reason why videos on youtube get on my nerves a lot of the time - there is never enough context or information to go along with them.
I'll bet dollars to donuts that before he showed the ball pythons he showed youtube his rodents.
I actually suspect he stopped the tape so the cameraperson could hold the body of the snake so he could reach for a spray bottle to squirt the snake with.
And, seriously, look at the size of the snakes head and the size of your hand.
I've made a Stupid Feeding Error with a nice big girl and got my hand struck, wrapped and constricted. No head smashing was required except mine against a wall for being so stupid.
Oh and they don't have fangs they have teeth - and they are very sharp but also very short. Any wounds will be superficial and very hard to see when you have wiped them clean.
He let the snake hang on like that to avoid hurting it. Their teeth angle backwards to help them hang on and if you just yanked your hand away you could end up pulling out a few of their teeth - which could be a way for an infection to get started.
You can usually get them to let go with a squirt of water or a little alcohol - but it's easier if you have free hands.
If you look the snake was giving him warning signs from the second he opened the tub. The way it was poised when he first opened it was a sure sign - if he had tapped it gently on the top of the head with a water bottle or something it would have been snapped out of feeding mode and he would have been less likely to have been bitten. Or, you know, not smell like it's dinner.
As a side point I think he was mistaken about that snake only eating live - if any of mine had done that I would have been relatively certain they would eat an appropriately heated F/T.
Play nice.
dr del