I wanted more of that scene too, but I think it's the point, it's ambiguous, because at first, he's very calm, and seems to understand David, but then Weyland starts asking all kinds of things, and then on top of all that, Eli is asking him questions too. I think he pretty much doesnt give a shit, or something else, God knows what David told him, and now that I think of it, David says at one point that everyone would like to see their father dead or something, maybe he told the Engineer to rip his head off and kill Weyland with it

But more seriously, he's awoken against his will, if he was the only one left and in cryo sleep, there's a reason for it. Is he supposed to be a guardian of the cargo?! Or is he sleeping, waiting for the arrival of his fellow buddies. Could be logical for him to be pissed off, being awoken when he is supposed to have been resting her for thousands of years. Plus, once he destroys everybody, it's like he's back on course, he goes straight to start the ship and leave, the guy does what he is supposed to do.