Pan Am B707-120 / 25Feb59 N709PA suffered in-flight separation of the #4 engine during a training mission north of Paris France. An PAA instructor pilot was demonstrating minimum control speeds at 8000 feet, the B707 stalled at an estimated speed of 120 KIAS and started into a right spin. The plane lost 2000 feet of altitude, before a violent recovery maneuver tore the engine and pod mount from the wing. Aircraft flew to London. Engine recovered in pasture near Pioneis on the Brest Peninsula.
With only 2000 feet of altitude loss, this could not have been a fully developed spin.
Sounds more like a post-stall departure.
Demonstrating Vmca at 8000 feet sounds a bit foolish, but those were the bad old days.