Okay, I get the gist of your question. First I am going to answer your question, then I am going to support it, and ref a short section of Rand's writings. I hope this method is not boring or trivializing the subject, because you have asked a very good question.
Is it moral or immoral to extort a large sum from an accident victim, and refuse to help unless he pays up? (qualification: Personal morality issue. It should be clear to all that Rand would have opposed law, social forcings, on the issue).
Immoral. Grossly, obscenely immoral.
That is stated irrespective of the following -
My duty as a capitalist and competitor ambulance driver is to drive him out of business, lest he sully the reputation of those in our trade and thus impinge on my prosperity in the trade.