Someone needs to subtitle the scene where David speaks to the Engineer with a "Your mom" joke. That would explain quite a lot.
Why did the Engineers leave a map to their military facility on Earth?
And apparently, the final Engineer was so pissed about David's your mom insult that he totally forgot about the toxic atmosphere. He just ran all the way to the escape module without a helmet.
And seriously... I'd like to see a film where things go wrong even though people are professionals at what they do. Seriously, it wouldn't have been hard with that kind of setup. Those characters were some of the greatest movie idiots I've ever seen.