It sounds like robbery to me, grab the money give it to her driver, which is a crime. No sex was sold, it was theft.
It is not much different from buying smokes at the 7/11, and grabbing the twenties when the draw opens.
So the clerk shot the person who grabbed the money.
The act of crime is the danger of life or property the law protects.
Jump over a bank counter, fill a bag, jump back over and leave, anyone inside or out of the bank can shoot you.
Robbers do not have to be armed to lose the protections of the law. That they are robbing is a presumption that they may also be armed, and not like witnesses.
Give me the money is often followed by Bang Bang, you are dead.
I live the next state over, if I found someone I do not know, or even do know, in my house without my permission, they do not have to be stealing or armed, just being there is enough reason to kill them.
In a local case someone saw three men loading his motorcycle in a truck, went out to stop them, and got a bullet in the head, he had a wife and baby. People doing crime are considered dangerous.
Lots of 7/11 clerks, gas station attendants have been found dead, after they handed over the money.
Shooting a robber in those situations would be allowed.
Robbing people there is a presumption you have some way to back that up, some force, and the amount robbed has nothing to do with it.
Hookers have left a lot of bodies in hotel rooms, down dirt roads, as it was just an in to robbery and murder. Eileen Waros in Florida, hitchhiked, told men she would have sex with them, took then to a rural place and killed them. Hooker turned serial killer.
The issue is thinking your life is in danger when jacked by a hoe. It is.