Fire exstinguisher could blew one of the engine's cowls... because to use the fire exstinguisher, you need to cut all connections (electrical, fuel, hyd, bleed) from the engines before dishcharging
That means, no way they could have done that on both engines
Dont mean to contradict, but discharging a fire bottle into an engine isn't going to cause the cowlings to detach
Don't think it would ever get certified in the first place if that happened
