Two characters both act, if not entirely out of character, far more stupid and selfish than their characters would reasonably act.
I don’t think it’s out of character. Daryl runs off alone, it’s what he does (he did it to search for Sophie and numerous other times over the course of the series). Daryl is a reckless character with strong convictions and a rebellious streak, so when he’s pissed and sets his mind to right a wrong, no one’s gonna stop him. Although he has gotten less reckless and more sociable in recent times, a person can regress after a traumatic experience.
As for Carol, I think she’s either confused or about to have a nervous breakdown, or in the process of having a nervous breakdown. Maybe Morgan really got to her; taken in this context, her rash actions become more believable. Anybody can reach a breaking point, especially a domestic violence victim in a zombie apocalypse.
‘The Walking Dead’ Season 6, Episode 15 Review: East – Forbes