Foolish naive hope Gleen, loved him and Merle the chaos envoy. The helicopter seems pretty suspicious given the world they are into. It could be important for the story. Rick was pretty ingenious by hearing about how the walkers sense humans for the first time. And how did they know that they smell in the first place. Anyways, they got out after all saving everyone but Merle. He dropped the key ans some tools, so I think he will come back.