Yesterday I rode along with the local air ambulance as an observer. We flew a child with serious head injuries who no more than 1 foot of the ground on departure stopped breathing. I found it really interesting that med flights typically do not use the call sign "lifeguard", they use it in only the most serious situations. Our pilot announced shortly after take off that he was a life flight and the controller came back and was like 'Copy, a bad one eh?' - for the 7 minute flight we had everyone moved out of our way. Our pilot even had to call the hospital to give our patient report cause we were so busy in the back - needless to say we had a number of people greet us upon landing!!