One day way back in 1974 I think it was, I was mowing the backyard near Lambert field in St. Louis.
All of a sudden there was a roar in the sky and I looked up to see 2 pair of afterburners going straight up. Bout ran over my foot with the mower I was so agape. Called pop who worked at MAc who said it was their new Eagle doing a "Zulu" takeoff he called it. I'm sure the guys in the tower enjoyed the show.
My buddy and I later snuck out into the airfield on the departure end where we would lay in the grass and watch the underbellies of jets go over, getting shook all around from the F-4s and F-15s after burners. Man did they shake the winders when they left Lambert.
I was an IT intern at Mac in 1990. I'll always remember that was the summer before Desert Shield because C130s dropped by to pick up all their extra Pegasus engines (used in AV-8B Harriers) for use as spares for Marine birds in the field.
Anyway, at the end of the summer, my boss (who had helped design F-15 components prior to transitioning into IT) set me up with a buddy on the production line for a couple of days of watching 'em build 15s and 18s. I saw a two takeoffs as you described -- I was told that the test pilots did that on just about every first flight.