The plot holes, logical fallacies, and inconsistent behavior of characters has already been covered a good 20+ times. Check earlier in the thread.
Dude petting the alien, removing their helmet because the air is "breathable", Weyland hiding on his own ship during a mission he funded, scientists randomly getting lost 5 minutes after the movie established they have state-of-the-art mapping technology, homegirl running and jumping around after a C-section, the "self-surgery machine" conveniently being on the ship.....ugh.....
No offense but people are tired of giving the same examples just for people to hand wave them away because Ridley Scott or Damon Lindelof gave a 5 page interview. If they put as much effort into the movie as they did interviews "Prometheus" might not be terrible.
Fred.