Section 21. No EMS personnel certified, accredited or otherwise approved under this chapter, and no additional personnel certified or authorized under section 9, who in the performance of their duties and in good faith, render emergency first aid, cardiopulmonary resuscitation, transportation or other EMS to an injured person, a person incapacitated by illness or an injured police dog under section 9A shall be personally liable as a result of rendering such aid or services or, in the case of an emergency medical technician or additional personnel, as a result of transporting such person to a hospital or such police dog to a veterinary care facility, nor shall they be liable to a hospital or veterinary care facility for its expenses if, under emergency conditions, they cause the admission of such person or such police dog to the hospital or the veterinary care facility.