* So was Sam's "infection" just one big red herring? Like, it really was just a stress rash and not the disease?
** Since she's still alive by the end of the movie and hadn't turned into a zombie or carbon-dust, then it's safe to say her stress rash was just a red herring.
* The movie suggests the comet's effects are what killed the dinosaurs. But since it reduces whatever is exposed to it to piles of dust where did all those fossils we found come from? If this comet had indeed wiped out the dinosaurs, humanity wouldn't have even been aware they'd ever existed in the first place, and paleontology as we know it shouldn't exist.
** Dinosaurs were around for 160 million years. Only the last generation was turned into dust.
* It's just mid-morning on the first day and Hector is already holed up in the radio station with a knowledge of what makes the zombies different? He must only have just gotten there!
** He had direct contact with ''multiple'' zombies, and witnessed a couple of them eating a girl. I'm sure he gauged his knowledge of the zombies from this.
** We don't know how early in the night people started disintegrating or roaming around eating people, either. He may well have ''heard'' some of the zombies snarling and chasing victims near his truck in the pre-dawn hours, and set out to contact others as soon as the coast was clear and there was enough light to see by.
* Throwing the guns away in a city garbage can when no one is collecting trash anymore is ''really'' stupid. You'd get the same effect from leaving them in a box in the middle of the street.
** It feeds into the idea of "the burden of civilization resting on their shoulders". They don't cross against the light, and so they also don't litter. But the idea of throwing away the guns is stupid anyways. Even if there's no more zombies, that's not to say that any survivors they meet after this are good people.
* Boy those power stations just keep on chugging, no one running them.
** In their defense, the movie only takes place over the course of ''maybe'' three days. There's a chance that the power goes down shortly after the credits roll.
** It ''really'' depends on the type of energy supplying the power. If the city is run on coal or nuclear power then the power would go down rather quickly. Oil or hydroelectric energy could sustain a city for several months without anyone running them. And if it's solar-powered, then the power could stay on virtually forever.
* Why aren't the kids in danger from the disease? Isn't the haze in the air going to do anything?
** I think it had to do with "direct exposure" to both the comet and it's radiation. If you were in an area that wasn't exposed to the outside you were okay. But if you were outside or had a window open, you were exposed. It looks like the people who were outside got the highest exposure and were turned into carbon-dust, while anyone with minimal exposure [[spoiler: like the think-tank scientists]] decomposed at a much slower rate. And I think it was said that the "haze" for the most part was the carbon-dust of the people living in Los Angeles and not actual radiation. When it started raining and the carbon-dust was washed away, the red haze went away too.
* Why aren't there a lot more survivors around? If all it takes to shield someone is a thin metal box, like the garden shed Sam slept in, you'd think there'd be thousands of people who happened to be sheltered in the same way, in a city as big as L.A. Anyone working the night shift in a building with metal walls, for example, or squatters living out of metal cargo containers.
** Because the focus of the movie is on the teenagers?
* If the comet did indeed wipe out the dinosaurs, how come anything at all survived to evolve into modern lifeforms? It's not like there was an abundance of metal-lined structures to hide in back then.
** Being underground apparently ''would'' have sufficed to shield the think tank, had they not left their ventilation fans on. Possibly there were burrowing animals that survived because they were under the soil with no air flow in their tunnels, or at least their eggs were buried.