People who go into some kind of dumbshit mode where they violate a rather basic social contract, by clearly indicating higher value for their crap than human lives? Yes, I'm getting a sense of acting irrationally right now: how about assaulting and trampling them? Hmm, small problem, while they deserve that and I think it would be completely ethical, their body will be yet another obstruction that will potentially cost others their lives.
You seem to be under the assumption that people in a true emergency situation have the mental coherency to even actively consider their own safety. The reason airline safety rules are so often repeated is that it gets people acting on 'automatic' without thinking about it, and even then there are various documented cases where airplane emergency survivors just sat in their seats without doing anything until someone told them to get up and off the plane.