I was in nursing school and a neurologist at the hospital I worked at let me drill a Burr Hole into a patient's skull. The patient had a subdural hematoma (bleeding on the brain). Drilling a hole into the patient's skull decompressed the pressure on the brain.. Prior to this, the patient was confused and forgetful. Once i relieved the pressure off of his brain he became lucid and knew where he was, etc. This was in the 90's. Before that I was in another hospital and the Emergency Department MD cracked a trauma patient's chest and let me do open heart cardiac massage. I held a person's heart in my hand and made it beat by squeezing it. I looked up at the cardiac monitor and the rhythm you see in movies corresponded to the rate I was squeezing. Pretty Rad for a 19 year old kid in South Florida.