Only remove the helmet if the rider isn't breathing, or he's vomiting blood. As the paramedic in the video said.
If the rider isn't breathing, the helmet has to come off for CPR. If you leave the helmet on, he'll just die or have brain damage. Only takes something like 4 minutes to die.
My helmet was removed last week from my crash, not a clue how it was removed or who took it off
I assume this was at a track? They should all know basic CPR stuff with helmets etc. It's the difference between you having someone wiping your ass for the rest of your life.