Final answer:
In the case of a patient in refractory ventricular fibrillation, the next action to take after administering a third shock would be to resume high-quality CPR.
Step-by-step explanation:
In the case of a patient in refractory ventricular fibrillation, the next action to take after administering a third shock would be to resume high quality CPR. CPR (cardiopulmonary resuscitation) involves chest compressions to help circulate blood and oxygen to the vital organs. It is crucial to continue CPR until the patient's pulse returns or until advanced life support arrives.