Incident Overview
Following a landing on Runway 25 Left, the aircraft held short of Runway 25 Right awaiting a crossing clearance. During this hold, the flight engineer initiated the auxiliary power unit (APU). Passengers seated between rows 20 and 22 on the right side of the cabin observed a 'bright yellow blossoming glow' emanating from the APU discharge duct. They erroneously believed this to be a fire in the right wing.
Passenger Reaction
Several passengers shouted "Fire!" upon seeing the glow. Two individuals rushed to the left over-wing emergency exit at row 19, opened it, and dove out onto the wing. Subsequently, other passengers followed them onto the wing. The panic spread to both forward and aft areas of the cabin, with passengers beginning to rush toward the doors.
Crew Response
The flight crew heard the shouts of fire and subsequently stopped the aircraft. They then ordered an evacuation of the aircraft.