Vitals or Mortals?

At the doctor's office the sawbones' assistant takes your 'vitals.' She checks whether your blood pressure, pulse, temperature, and O₂ uptake are 'within range.' None of this would be necessary if you were not a mortal man on the way to death. But the young assistant is not interested in trading witticisms with an old man, so you refrain from remarking that she is about to take your 'mortals.'