Oh, and can anyone explain to me the presence of chain saws on an advanced experimental base on Mars? I can see them planning it now "Oh, we'd better pack some chainsaws just in case something goes terribly wrong and monsters from another dimension need some weapons, because there isn't any wood around here so they be useful for anything else" And why do guns run out of bullets but chainsaws not run out of petrol? (Or maybe they do now)