Someone gets gutted next week and rosary beads are laying in a pool of blood at the scene ( coming attraction for next week ). Hmmmm. Gotta believe Morgan is involved in the search for Carol ( final scene).
I'm just guessing, but I think Carol finished off the walker just outside the gate (the one that had the rod through its cheek) and then just hung her rosary there. One of the last things she said to Daryl was something like, "you were right... You should have killed him... I knew it when you said it." I think she might have gone "godless" and is going out to wreak havoc on Dwight, or perhaps even Negan himself.
I just read an article that said in the comics, a different character takes the arrow from Dwight in almost idental circumstances. So perhaps, that will spare this other character (Glenn, perhaps?)