So, in the previews, we see Rick with a look of shock, the underacting is showing something brutal has just happened. I think I know what it might be. We see Rick obviously bloody. Did he find someone dead? I don't think so. In the New Zealand and Australia promos, we see Joe's group (or at least a few members) taunting Carl in a car. When we see Rick, he's leaned back on what appears to be a car. My idea is that Rick locates Carl in danger and slaughters Joe's group, kind of like what he did with the marauders in the comics, only this time, I think it might be a bit more harsh and savage. Now, this does bring up some questions: Is Daryl or Joe apart of this? If so, what would Rick do? Will Rick make it to Terminus if this happens?
Now, obviously, I'm not clairvoyant. I just think it would be interesting to see Rick go apeshit on these guys for dramatic effect as well as for preparation on the "sobering up" that Alexandria does.
Just my theory.