Not a bad episode, I didn't really find it that "intense" as some on here apparently did. Just because having read the comics I (and others) figured a few weeks ago (when Lizzie was smothering baby Judith) that they'd be doing the Billy & Ben plot with the girls instead.
Suppose we don't really need spoiler code for this?
As in the comic post-prison Ben kills Billy in a similar fashion and is found by the group, who don't really know what to do with him at first. And Carl is the one who sneaks into Ben's tent in the middle of the night and shoots him.
(whereas in the show they've already had Carl do his 'ruthless killer' stuff at the very end of Season 3 when he shot that kid from Woodbury)