Factual error: Winter in Antarctica would not have a night and day as portrayed, with the amount of light changing so much during the course of 24 hours.
Factual error: The very first time we see Kate, when she is examining the extracted specimen, she is listening to music on molded plastic headphones that were not available in 1982. Smaller headphones such as these, designed at the time for listening to Walkman-like portable equipment would have had a metal band going over the head, holding the earpieces in place.
Factual error: When they decide to disable the snow vehicles in order to keep anybody from leaving the base, they decide to disable the engines by cutting the spark plug wires with mechanics sheers. The only problem is that the engines in the snow vehicles (you can hear this to be true) are diesel engines - and diesel engines do not have spark plugs at all. The plugs in the movie were for gasoline engines.
Chosen answer: By disabling the snow vehicles, they are making sure that the creature can't use them to escape from the quarantine zone. Since the creature can assimilate anybody, it would probably know how to use one.