A 28-year-old man with a stab wound to the abdomen is brought to the emergency department with active bleeding. He is conscious but anxious, blood pressure 95/60 mmHg, heart rate 125/min, respiratory rate 24/min, SpO₂ 94% on room air. He ate dinner 1 hour ago. The surgical team requests immediate anesthesia for emergency laparotomy. During rapid sequence induction, after administration of the induction agent and neuromuscular blocker, the anesthesiologist observes fasciculations followed by a brief period of apnea. Which of the following best explains the mechanism of the apnea observed in this patient?