The correct answers to these open questions are the following.
Has the Medical Center violated the antitrust laws?
Not really. Antitrust laws were created to help consumers to have different providers of goods and services, offering better prices based on competition. When the company bought the other hospital it doesn't mean that they are having monopolistic practices.
Was it ethical to deny treatment to a patient?
No, it was not ethical. What the hospital is doing is not ethical because Clarice is in need of medical treatment although it is not considered an urgency. The hospital has many medical specialists that are not always 100% of the time attending urgencies, so they shave the time, knowledge, and equipment to help patients like Clarice.