I almost did that at the IMAC Nationals last year. Came out of a loop and was straight and level for the end box maneuver. For some reaon, I had a brain fart and pushed down instead of pulling up. The nose started down so I pused harder. Luckily, I realized what I was doing and saved it with a couple of inches to spare. Zeroed the maneuver, felt really stupid, but saved the airplane - guess it ain't all bad!!!