I could not get the video to play so could not see how you pop the heads.
Over the years I have found my way to do this with great results. I hold the
shrimp in my right hand. With my left thumb and forfinger I squeeze the lower
part of the head making sure the spike is resting against the forfinger. I then lift
up and away from the shrimp. Most of the time the vein comes out with the head.
I have also learned that the part of the shrimp that lays under the head is not
removed with the head. More shrimp to eat. I learned this thru experimenting
while cleaning the buggers.