What happens when the two oldest professions in the world meet?

I was recently approached by a GP seeking my advice about a potential boundary violation of a sexual nature.
This middle-aged male GP, who is not a patient of mine, was recently divorced and had no current appetite for any new personal relationships.
He did not want to become involved in any online, social media or hook-up networks and had approached an escort service in a neighbouring suburb.
At this service, he noticed that one of the ladies present had been a patient of his. He remembered that he had seen her on one occasion, some six months before, when she requested testing for STIs.