My story is very similar to yours, Doodle.
When Sam (R.I.P.) was at the vet years ago, he had fever and was in a lot of pain from an absess on his tail. I warned the vet that muscular, 11-kilo Sam was feeling badly and was very cranky, but the vet and vet tech both said,"Don't worry, we can handle him.", and insisted that I leave the examination room.
About two minutes after I left the exam room there was a yowl like a mountain lion, and muffled cursing from inside the clinic.
A petite vet-tech came running out to get me, with this frightened look on her face, pleading,"You've got to come get your cat!". I said, "Oh, Sam is just scared. He'll be okay.".
I entered the exam room to find Sam in a corner, holding off the vet and two assistants. His eyes were completely dilated with fear, and a third assistant was bandaging her hand by the sink. I softly said,"Now, Sam, I'm here. You don't have to be scared."
As soon as he heard my voice, he sniffed the air and relaxed a little, but still had one paw a little up, ready to strike. I just kept softly speaking to him as I walked up and let him sniff my hand. As soon as he was sure it was me, he relaxed, purring and nuzzling my hand, telling about the bad people who had scared him so. Poor Sam had been terrified, and was in pain, and his instincts took over. He was calm after that, and I told him not to fight the vet or assistants because they wanted to help him.
Even in his state of terror, he knew that he was safe as long as I was near.
Later, the vet tech who was bandaging her hand in the exam room told me that Sam was an angel for them, after I spoke to him.
R.I.P., Sam, you really are an angel now.
sorry for going off-topic