Picked the wrong lead.
Mild Spoilers
You can keep Sheri in the movie. We get it, it's fun to cast people you like. Killing her off half way would have been such a nice twist though, no? It'd give that nice "there's a real chance nobody's making it out alive" feel to the rest of the movie and would have given space for...
MEG FOSTER to the lead the film. The heroes were all pretty underdeveloped, but hot diggity if Ms. Foster didn't bring her A game to the movie. She sold that business and would've much more believably held her own against "the heads". IDK. I really liked her in this and wish she'd made it.