Seems to me like they knew how to handle the airplane!
They could not turn around so the reversed all the back down the runway and then took off
Mhhh, not a Gulfstream driver, but is reversing as far as 2700ft actually approved ?
All jets that I flew yet had a "do not use reverse thrust to back airplane" in the manual.
Mind you, reversing without a mirror is hard work, whenever I did that in a KingAir I certainly did not like it - and that was never more than a few meters.