In section B of the endorsement (Who Is An Insured), it states that if the insured is an individual, he/she and his/her family members are covered under the endorsement while pedestrians if struck by any auto.
This would seem to suggest that the named insured and family members have unlimited med pay coverage for ANY auto accident in which they may be injured. That scope of coverage would seem to be far broader than any circumstances related to the scope of intended business operations. For example, if the 8 year-old child of the insured were to be injured (as a pedestrian) by an auto while walking through a parking lot at a grocery store on the weekend, it would appear that the endorsement would provide coverage.
That scope of coverage would not seem to be intended, but I see no wording that would preclude such coverage.