Incident Details
Following landing, the flight crew attempted to start the auxiliary power unit (APU) during taxi to the gate. The APU torched, and flames emerged near the right wing of the aircraft. A passenger seated near a window observed the fire and shouted a warning.
Evacuation
A passenger seated on the left side of the airplane near the over-wing emergency exit opened the exit and initiated an unwarranted evacuation while the aircraft was still moving. The cabin and flight crew attempted to restore order, but many passengers had already exited onto the wing and were opening other doors. A flight attendant then activated the evacuation alarm, and the flight crew brought the airplane to a stop.
Aftermath
The airplane was completely evacuated by the passengers before being towed to the gate. No further details on injuries, damage, or aircraft specifics were provided in the source.