Lorraine is unsure that taking the Colonel to Atlantic City is such a good idea. After all, the old man's not in the best of health. He has severe diverticulosis, a disease of the digestive tract that can cause quite serious and debilitating pain. Indeed, as Lorraine tells us, the Colonel has been screaming in pain due to his condition and is therefore in no fit state to be making any kind of trip.
Despite Lorraine's concerns—the Colonel might actually die from his ailment—John really wants to go to Atlantic City; he thinks that it'll be a lot of fun. As for the Colonel's screaming in pain, John ventures that it might be due to gas, as in a build-up of gas in the stomach. In any case, he's more than happy to defer to the judgment of Dolly, who insists that the Colonel should be able to go to Atlantic City. Why? Because it's what the Colonel wants apparently.
However, Lorraine is unconvinced by this explanation. She senses that Dolly's holding something back, some secret that she's refusing to divulge. Anyway, the decision has been made. The Colonel, along with Dolly, John, and Lorraine—but minus Gus, the Colonel's dog—are on their way to Atlantic City.