No idea... that's just how that doctor does nerve blocks. She'll never let him do another one, and she straight out told him that. At the time, neither of us knew anything about how the procedure was usually done. She got pretty angry when she found out later that most people get knocked out for those...
When the doctor is doing a nerve block - pretty much the patient has to tell them when they have it right. They only know the approximate area to try to set the block - they move it around inside (that is part of where the pain comes from) until they get it right.