IIRC, the amount of time from when a person has no pulse (and thus, no oxygen replenishment to their brain) is six or so minutes, whereafter they would be considered brain-dead, due to glycogen depletion. Understand, I am not a doctor, and I did not follow the ambulance to the hospital from a scene to find out.
If you get to thinking you’re a person of some influence, try ordering somebody else’s dog around.