First rule of fires, cover your face and stay low to the ground. It's
not the fire that kills most it's the smoke and carbon dioxide poisoning. If possible don't run but calmly walk to the exit, try to keep aware of your surrounds.
Just a P.S.A. to all the readers.
@KINGwaldo I agree with you except maybe not crawl in the oil spill.. maybe bend over low while walking.
@Wilhelm_Stenvall Yes they do, she probably should have walked some (safe) distance from the fire, found a wall, then crouched low as she could holding her shirt over her face with one hand and using her other hand to touch the wall as a guide to the end of the tunnel. In most countries there are emergency exit signs along tunnel and subway walls.
It's important to find a wall in a big tunnel like that because the
smoke can effect your thinking and you could start wandering in circles.
The people panicking and running may have just been taking in huge lungfuls of toxic smoke and that's why the man(the body she saw) fell over. Or he could have had a preexisting condition like heart failure or intern damage from the bus accident.
Edit: You all can see by the mass of text this subject kind of triggers me. The city I live in the suburbs of has a policy of giving free smoke detectors to all citizens because every winter so many familys have their houses burn down trying to keep warm here. It's a tragedy that sits rather close to home with me.