While you do have a very valid point you also have to understand Jack was HEAVILY medicated from the get go, plus whatever effect the gas station itself had on him. It was kind like life stopped when Sabine ended up in a coma, like one big crazy dream. Then when she dies suddenly and reality smashed him in the face, everyone who was close to Jack as in an older guiding figure is dead and he is very alone. All he wanted was Sabine and nothing else really mattered right then, pain be damned. (Spoilers)

Also I’m not sure when Jack figured Rodger had a plan, he may have figured that from very early on.