As far as why one would choose one gas station over another of the same kind, I used to drive to one specific local station (often out of my way) simply because they had an app that allowed me to pay without pulling out a credit card (I'm sure most stations do, but some require their own credit card - meaning if it was a Shell station, one must have a Shell card to use the Shell app to pay and we do not choose to have gas credit cards). Further on that line, while there are several of the same stations near me, some required that the user scan the QR code on the pump while others allow you to simply select the pump once you are "linked" to that station. While this might have no bearing whatsoever on Alan's case, it's a small note that tiny details can alter consumer behavior and possibly there was something similar that made him go to that particular station. Or possibly it was just that he didn't realize he wanted/needed gas until that very moment.
In any event, this case weighs heavy on my heart, and I hope that Alan is somewhere safe and will come home to a family who loves him soon.