The subject of tailpipe fires and passenger evacuations is covered on an instructional video put on the web by the FAA (New England Region, -Standards section)
The naration states something to the effect that the tailpipe fire as shown in the video may be spectaculor in appearence although typically slortlived when detected and handled by the flight crew (motoring and fuel cutoff). It also shows the recomemnded intercom between the cabin crew and flight crew in such events before putting passengers out the door and infront of running engines.
There have been three major events on widebodies (A330, and two B747-400) where the tailpipe fire serously damaged the wing because the pilots had to shutdown the engines and leave the fire still burning upwards under the wing using up residual fuel and no airflow to blow the fire in back of the wing, when the passengers went down the chutes without the flight crew's command.