Meanwhile, back at camp, Lori and Carl are alive- and the assumed widow Lori is now sleeping with Shane. That's a bit awkward. At the mall, though, as needed for the narrative, Rick saves everyone by thinking outside the box. A good thing, too, as it was him who put them in danger, but it's all a good bonding experience. But Merle's racist thuggishness means he's cuffed to the top of the building as the zombies attack. He's doomed, surely?
What else? Rick sees a helicopter, which I'm sure will be relevant later. But we're still in the realm of set-up, albeit damn good set-up.