A 34-year-old woman from Kerala presents to the emergency department with severe hyperthermia (core temperature 40.8°C), profuse diaphoresis, and tachycardia (HR 128/min). She reports accidental ingestion of a pesticide 2 hours ago while working in her agricultural field. On examination, she is conscious but agitated. Her respiratory rate is 32/min and blood pressure is 158/92 mmHg. Serum electrolytes and glucose are normal. A urine dipstick shows presence of a yellow-green fluorescent compound under UV light. Which of the following best explains the mechanism of her hyperthermia?