If it had been a tensile failure/release of the prop shaft, the whole prop would likely have shot straight ahead, missing the aircraft completely. There is some precedent for this.
Most any other mode (broken blade, gear case breakage, etc.) could release parts in the plane of rotation, penetrating the fuselage. This could cause enough imbalance in the core engine that massive rotor/stator clashes could happen, causing stalls/surges that would seem "explosive".