"...but I know you knew some things I didn't." This was something Rick said to Carol before he asked if the group could join her. What does Rick mean? Does he regret banishing her despite still believing she did wrong in killing Karen & David? He obviously had some misgivings about her being out there alone. What things did he think Carol knew? Maybe that the illness would get so bad that they wouldn't be able to defend themselves against the governor? Or that Tyreese would ultimately be able to let Karen's death go and not try to kill Carol? So cryptic.