I know I gave "great concern" to my initial civilian instructors. Later I had people I was training scare me too, even experienced pilots do dumb things ocasionally. Had one guy riding co-pilot (who had 500+hrs in the same plane) feather both engines on short final one day. Now that ticks you off. He was adjusting the props and went past the detent.[:@] He didn't get to fly with me again - EVER. Oh - I got the plane down safely.