I can see that happening as a result of her learning that Carol killed the other two. "Well, Carol did it. Mika was holding us back as much as the sick people."She's definitely going to flip and kill someone. My thoughts on who:
- Her sister, Mika. This seems the most likely to me because she's pretty disposable as a character anyway and it would be really cruel. Lizzie also gets quite upset at her sister.
Mika is only a runner at this point though, which isn't too detrimental. If anyone was holding them back, it's Judith with the crying and just generally all the issues that come with a baby. This would be the ultimate exercise as a result of Carol's pragmatism. The baby is just as likely to get them killed as the sick people were. Carol might not be able to go that far, but Lizzie could.
But the thing is, I don't know how much rationale Lizzie is really going to have when she snaps, because after all she is crazy. She could kill anybody else who I didn't list for no reason at all.