The most memorable training experience was in paramedic school doing my clinical at a local hospital. 

Under the direction of the doctors and nurses,  I was charged with the supervision of a patient  on life support - starting of the IV , monitoring the progress, preparing and pushing the meds ordered by the doctor.  After a while the Dr. ordered the disconnect of the life support and pronounced the patient dead and issued a time.  The doctor then said to all in the trauma room that it was done,  and asked me to disconnect the IV's,  cardiac monitors, and all other ancillary hookups 

All personnel left the room.  It was at this time I observed a pulse in the carotid artery of the patient and immediately requested the doctor come back into the room .  The doctor returned and began to palpate the carotid artery, and promptly found a pulse.  He then exclaimed "YOU HAVE JUST SAVED THIS LADY’S LIFE, CONGRATULATIONS"!

Following my rotation,  walking out of the hospital I met with a long time ham radio friend I have known for 15 years. He mentioned that his mother was in the very same room I was working in and thanked the staff for saving his mother's life.

I didn't let him know that I was the one who observed her pulsing carotid and brought it to the doctor's attention, but thanked God that I did what I did.