Things you noticed after watching it again

Picked up a little more after the 2nd viewing. Paying the special attention to when they wake up the engineer at the end of the film. Reading the body language and facial expressions of the engineer provides a little insight. The engineer doesn’t seem to be surprised at first to be surrounded by a bunch a humans. IT is only until the first English words are spoken does he look startled and surprised. Is this because of him still waking up from the deep sleep, OR is it because he has been around some form of humans before (maybe driving the large ship at the beginning of the film?) Also, the engineer seems very concerned and interested in what Shaw is saying, he kneels down a bit and looks like he is either trying to understand what she is saying or is picking up on some of what she is saying, which is Shaw asking why do they want to destroy us. At that point Weylan tells the soldier to "silence her" and the soldier knocks her down with the shotgun. The engineer’s attention then turns to the old man barking out orders and the android; the engineer’s mood clearly changes once David speaks. He knocks everyone down, let's Shaw run away, and then starts the ship towards earth. That squid thing at the end is nothing but a giant face-hugger of some sort. Pretty sure the alien at the end is a queen (I think the sack gives that away). I don't think it is a coincidence that at the moment they are about to go and destroy earth (2000 years ago) that all of a sudden earth is saved by a lucky lab accident. Did the engineers bring back humans to that site for experimentation, and maybe one or more were able to sabotage the engineer’s plans, maybe a human test subject/prisoner sacrificed himself 2000 years ago and started the lab outbreak to stop the ship from coming to earth? Either way, I think something decided to save earth and unleash the aliens on the engineers. I really don't think the engineers are engineers at all, I think they are just brutes designed to do the "dirty work" for whatever is in the giant ship at the very beginning of the movie. All in all, just as entertaining the 2nd time, and may have given me a little more insight into what a prequel or sequel MIGHT include. Oh yea, and the sacrificial engineer looks different from the engineer at the end. The engineer at the end almost looks to be biomechanical from the neck down. The shotgun bullets just deflect off of him. And, it doesn’t look to be a suit when the alien breaks out of him at the end.