I didn't even notice Archer getting in the way of his own orders, but having studies physics for a year, I was really pissed off by the comet's gravity. There should hardly be any to speak off, and they should use lines to prevent themselves from floating into space when they jump too enthusiastically. I was able to ignore it at first though by thinking that they have magnets in their boots that are attracted to ice or something, but then Travis managed to break his leg. Even though he weighed about 15 grams. And when the shuttle (weighing about 400 grams) started caving in the comet, it really seemed like they were going out of their way to annoy me by making even the most implausible explanations wrong.