SS
It stayed up because it carried sufficient fuel to maintain feed at extreme attitudes.
I see AnFi' s point.
As the useable fuel is exhausted, depending on tank design, there might be a period where the feed is interrupted momentarily, which might, depending on engine and ignition characteristics, lead to popping and banging as witnessed, and a very confusing problem for the pilot.
As for testing the run dry characteristics on the ground..... pointless. No simulation of the attitude changes in flight.