You misunderstand, he's not a guide because he's intimately familiar with every part of Antarctica, he's a guide because he has survival skills, he knows the ecology of the place and perhaps most importantly he has a command of
snowcraft. If you like, perhaps he led the team that originally built the base and he does in fact know the surrounding area to a degree. I could easily edit that into his bio.
It's just that I don't think there are any experts on navigating the region. I'm trying to imagine who might qualify as an expert (Roald Amundsen?) and what exactly they're intended to be doing in the base, given that as a general rule you don't wander off very far from it unless you're interested in the local geology or some such thing.
But hey, if the military feels we need one, why not?
Around 1989 I think was when the
30th Antarctic Exp. occurred. There are still ventures there today. My point being that a lot of people have walked on that continent, many of them civilians, many of them not famous at all for doing it. Even so, as I said before, it doesn't matter if the individual in this case has ever set foot on Antarctica. Your hypothetical guide probably hasn't been to Antarctica but he would definitely be a veteran in journeying and surviving on a tundra, which is the whole point.
Say the helicopter and radio aren't working (or for some other reason help can't come), wouldn't you say his presence drastically increases your chances of surviving until contact is reestablished or the helicopter is repaired? Worst case scenario you guys have to wait a year until anyone even realizes something is wrong when the boat makes it's biannual trip and finds the supplies they dropped off last time were never picked up.