Yes, another theory for Gakkou Gurashi! And it is kinda late as the next episode is tomorrow...
**SPOLIERS**

This is a theory of mine for episode 10 of Gakkou Gurashi!

**SPOILERS**

So... I think everyone is going to die (well... turn into zombies at least).

Or... At least most of the cast.
And there's been a countless number of deaths in the anime, so why not kill off more?
First off it was Megu-nee.
Then Kei...
And there was also a countless number of students and people in the mall and people in Japan who turned into zombies.
(How many people turned into zombies? たくだん(too many to count, takusan written in romaji))
So who's next?
Probably Kurumi, since she's already turning into one.
Another person will probably be Kei, since she will be too busy mourning over Taromaru and I don't blame her. It was right after Taromaru started getting comfortable around her.
And I think Rii-San will turn into a zombie because she doesn't seem that strong. She doesn't help clean the water tank in one of the episodes. Also, she doesn't go look for Taromaru, she just stays in the club room. I think she can be pretty threatening to the other club members. I think she hides her weakness.
And Yuki. In the preview for the next episode, we see Yuki going somewhere. And it's only Yuki. It seems like she might be the only one who will stay human.
And now for zombies. I had a theory on how the zombies started. I think that someone became insane and from that a zombie was born. In the episode where Megu-nee was watching the video about zombies, it was mentioned that the people were acting crazy. Also, the zombies sway their arms and sway when they walk. This is different from how zombies are usually portrayed,  where their arms are out and they are walking slowly. Also, Megu-nee's writing looks really crazy. It seems like she is insane.
So another theory. I think it takes time for a human to turn zombie, as Megu-nee was writing about everyone. Something that supports this is that Kurumi didn't turn into a zombie right away, it's taking her time.
I have not read the manga, so these theories have already been proved or disproved in the manga. (I haven't read the Charlotte manga either.)