A SURVIVABLE crash of the jet - (unlikely - very, very few jets crash with people still alive who need to evacuate.
Survivors who lived through the crash, but are trying to get out ...
A fire that begins after impact, but spreads more rapidly (because of the resin/fibre construction) than a standard resin/fibre/aluminum/honeycomb construction!) ...
More people die after the 787 crash than would have otherwise.
Yes - these types of crashes have happened. But most jets auger straight in, at speeds way too fast for any to live. In TN recently, few survived the crash, and the fire-resistance of what was left of the plane didn’t matter. Seat location and luck of the impact forces were all that mattered.
I’m no engineer, but carbon fiber has been used in race cars for a number of years, and the fire hazard in race cars is lower than it’s ever been. Back in the 60s and 70s, race drivers were getting fried all the time - Bandini, Siffert, Schlesser, Courage, Williamson in F1, Sachs, McDonald, etc at Indy. Now it’s extremely rare.