Oh, the "supermanning across the gym" problem! One of our L10 guys never did solve it, so now he does a double front half out. Most gymnasts, given enough time and drills, do figure out the proper timing to do a good laid out flyaway, but it can take a while. If it's not there yet, better to keep it in the gym and keep working the drills. If you look at some men's high bar routines on Youtube, you can watch dismounts and see how they tap into the dismount swing to kill their momentum enough to do what they want to do. My son went through a superman phase a few years ago; thankfully it was brief and he got over it before meet season. His coach has the same policy about not competing wild flyaways with low releases as your coach -- dial it back to a swing flyaway and don't scare the pants off everyone.