I am not your student but I'm your student. You are a wonderful teacher. I love watching your videos. I am studying late in life! I am 60 plus. My experience in life tells me that your students have no reason to complain for ANYTHING in relation to studies whatsoever.
Excellent question! 2:1 HB is a special kind of HB where there are exactly 2 P waves per QRS. In that case, it's not possible to determine if the rhythm is second degree type two or third degree, so we just call describe what we see - 2:1 AV block.