Yeah, I don't understand the criticism aimed at them running from the ship. It's a pretty stupid criticism. People act illogically in real life all the time. Them doing the same in a film is not necessarily a flaw.
That said, I didn't really like the film. While it looks stunning and the first half of the movie is decent, towards the end it starts to fall apart. A lot of the characters motivations aren't really explained, and the film never really attempts to answer the questions it brings up. While the door is left open for a sequel, and presumably some of the unanswered questions may be explained in that, leaving everything for a follow up movie seems like a cop-out.