OOOOPS -- I guess John meant burning jet fuel from the airliner ! (thanks Phil !)
...but if nothing gets through the wall, what difference does it make ? (ignoring destruction of the "balance of plant" for the moment).
As we saw in the WTC disaster, much of the fuel was gone in the initial fireball. I suspect this would be even more so in the case of a disintegration of an airliner on the outside of a containment dome.... in contrast to the WTC, where a significant fraction spilled throughout the interior of the structure and ignited any combustible materials there....
Also, in chemical/petrochemical industry, large concrete basins are used for emergency/accidental spills to safely burn-off the flammable liquid.
I think there is a big difference between the relatively skimpy & fragile fireproofing of steel structures in highrises, and rebar embedded in four-foot thick concrete walls !
Jaro