Would it have been better for Ms. Torti to argue that she was providing medical treatment and have the court deal with the issue of what constitutes medical care rather than the issue of immunity?

Answer: No, it would not be a better idea

Explanation:

If Ms. Torti argued that she was providing medical assistance, then the Law would protect Ms. Torti's immunity. But, had the questioned would have arose if Ms. Torti was medically trained or she was aware that it needs medically trained personnel to provide such care at a scene of emergency. This would be a direct attack on the defendant's cause. I do not think that it would have been a better idea.