Here we have a policy of our staff not moonlighting as a medical expert for medical malpractice law firms, since you’re paid an annual salary. Do you have a problem with that?

You should never have a problem with any policy of the place to which you're applying. Many hospital-based physicians will have to accept such policies, so before your interview you should decide whether you are happy with just the one salary. For most, this will not be an issue, but the problem can become fuzzy when you are subpoenaed to be a fact witness. Make sure you assure them you are clear on the policy.