*I gave this thought it's own topic which should be up shortly... Walter asking Daniels about Nausea, etc. lead me to think about pregnancy (as we already know that she and the captain are a couple). A possible red herring, to lead us in the direction that Walter might have ulterior motives? Follow me on this one:
Any chance Franco's character has been infected by the black goo already? Remember Holloway had a fever before things hit the fan, and looked to be in a similar state before the 2nd trip to the pyramid. Maybe the 'Judas' has access to the goo via some other means and is testing out the effects the same way David did? Perhaps via an unseen salvage mission to 223 sometime between the 2 movies by the Company? The characters seem surprised the captain here isn't feeling well, as if the onset was sudden.
The 'Judas' may even be aware of the distress signal on Paradise prior to the crew's knowledge. Wouldn't that be just like Weyland-Yutani - Toting thousands of human embryo's with access to the ultimate bio weapon ~a weapon which has now been further enhanced by a brilliant operative already planetside? One with 10 years of uninterrupted time to experiment in a self contained environment.
"This ain't their home. It's an installation. Maybe even military. They put it out here in the middle of nowhere because they're not stupid enough to make weapons of mass destruction on their own doorstep"... hmmmm
Suddenly, Ash's, "I admire it's purity" takes on a very dark meaning - one the history of the world is all too familiar with.