While your doctor carries malpractice insurance, ideally, you would like to sue more entities than just the doctor. Having more defendants with deeper pockets is always better for your medical malpractice lawsuit.
Here, what you are really looking for is the ability to sue the hospital or medical practice where the doctor works. So long as they employ the doctor, and the doctor’s negligence was within the scope of their job, your attorney could add these entities to your lawsuit since the doctor is their representative. Hospitals may carry even more insurance than the doctor, so the policy limits of their coverage could be even greater.