...or a major malfunction?
Seriously though - imagine what it's like to be SLF, and hear a loud bang then experience intense vibration.
You'd be ****ting yourself.
Hell - I'm a pilot and I'd be ****ting myself (jeez, that sounded like a blade cutting loose, did it miss the cabin, take out any hydraulic lines, is the whole disk next?).
"Ladies and gentlemen, obviously we have a problem with one engine - the plane can fly perfectly well without it running. We're going to shut it down and quickly drop to a lower altitude as a precaution, please ensure you're seated with your seatbelts firmly fastened...."