I wouldn't have asked this forty years ago, but: Suppose so many of the PAX were calm because it simply didn't occur to them that they were in danger? A great many of the comments I see on line (but not here) show a delusion that the physical world is so thoroughly under human control that if somebody doesn't make or allow something to happen, it doesn't happen. So while a fire outside is a problem for people outside, nobody is going to let it come inside - so, no problem inside.
Or am I just a paleoflatus grumbling about 'kids these days'?