I speculate that more than just fouled plugs or an straight forward engine shutdown are involved. Shutting down and securing one of four engines should not rattle experienced pilots. If an outboard engine were to have been on fire, and would not feather, the sense of urgency to get on the ground, coupled with a plane with lots of drag from the stopped prop would challenge most pilots, and turn an event from bad to worse. I have empathy for pilots watching the ground come up at them, and being unable to arrest a descent.