This patient presents with severe head trauma, unresponsiveness, hypotension, tachycardia, and apnea (R = 0). NREMT education stresses that apnea following head injury is a critical red flag for increased intracranial pressure (ICP) and potential brain herniation.

Option B is correct because brain herniation occurs when swelling or bleeding within the skull forces brain tissue downward, compressing the brainstem. Compression of the brainstem can result in loss of respiratory drive, explaining the absence of respirations. Elderly patients are at increased risk due to cerebral atrophy and fragile bridging veins.

Option A is possible but does not directly explain apnea.

Option C is associated with sudden cardiac arrest after chest impact, not head trauma.

Option D would present with respiratory compromise but not directly from a forehead injury.

NREMT emphasizes rapid airway management, ventilation, spinal precautions, and immediate transport for suspected brain herniation.