I'm pretty sure Carol will return. She will probably find the Gov, or maybe the Alexandria safe zone as mentioned in one of the first posts (sorry, dont read the comic, not sure what this is...). She has already had such a huge impact on this season that they cant just write her off just like that, she will definitely be given a bigger role... possibly like what they did for Andrea... her own litle side story.
As for the Darrell and other dude confrontation, that was pretty intense. I am unsure how I feel about that guy, seemed like trouble when they first introduced him... so who knows. Feel kinda bad for him though.