Allen the Troublemaker, a 19-year-old college student, was rock climbing when he fell 30 feet to the ground. Paramedics arriving at the scene found him lying in the supine position, unable to move any extremities and complaining of neck pain. He was awake, alert, and oriented to his current location, the date and day of the week, and the details of his fall. His responses to questioning were appropriate. He complained that he could not feel his arms and legs. His pupils were equal and reactive to light. He showed no other signs of injury except for several scrapes on his arms. His vital signs revealed a blood pressure of 110 / 72, heart rate of 82 beats per minute, respirations of 18 per minute. Vital signs were taken again at the hospital and were as follows: blood pressure=94 / 55; heart rate=64; respiratory rate=24 (with shallow breathing).Why did Allen's heart rate and blood pressure fall in this time of emergency (i.e. at a time when you'd expect just the opposite homeostatic responses)?