There could be a whole heap of scenarios to this one. Stretcher or no stretcher this is very possible as there is often more than one A/C parked next to each other being services with equip etc whilst an engine is running on another plane. Parked next to each other but facing opposite directions has the cargo door perfectly lined up with a spinning prop arc on the other plane.
I've seen this very situation come very close a few times where someone is starting up the plane beside another plane being preped ready for a flight with a stretcher being taken off. This is then left unattended momentarily it's a windy day the trolley/stretcher starts rolling, very nasty if contact was made.
It's a very dangerous environment around Ambo planes where you can have re-fulers, ambo's, ambo trucks, walking patients, patients escorts, equipment etc all whilst within only a few meters of a plane that has two engines running.
So am not surprised if this thread is true.
Wmk2