They showed a young clean shaved different Hickey getting his work papers at the beginning and then at the end they show our Hickey arriving for duty with the facial hair. He's a cra cra who maybe killed real Hickey and took his work papers. When the guy, checking him in, notices Hickey doesn't know what he's doing and says something about trying something new and Hickey says 'trying everything new'. ALso, notice the storage locker box he's standing by, that he's assigned to. It's the same one Capt Crozier closes as they leave the ship. Remember the close up of the initials...and Crozier looks at them too (I think he runs his fingers across them). Initials were EC. Not CH for Hickey. Also leads one to wonder about the C in the EC initials....hmmmm.