Before Heavy Duty, all options for getting hired into Expedition either involved serious, easily verifiable work or at least had a relatively high Persuasion check. But now simply returning from Compound does the trick, and that can be done completely trivially by just recharging the train and walking back. The Ladelman commentary doesn't sound convincing either. The situation can be summed up as "I was (supposedly) hired by some train operator that Ladelman arm-wrestled with, and (supposedly) he and his team are now dead and I'm the only survivor". It's completely unclear to me why this story should convince Briggs to hire you for Expedition.
I don't know whether the game is past the point of improving such things, but one very low-hanging option would be to require the player to wear or possess one of the Exoskeletons when interviewing. Gameplay-wise, this ensures that the player at least got to Exoskeleton Assembly room, and story-wise, Briggs should be impressed by Exoskeletons just as Protectorate Marines at the Rig are.
