How does MUTANT Fifield get into Prometheus?

Hollow Way
MemberOvomorphJune 05, 20121393 Views7 RepliesSo here I am American Hollow Way who has not seen the film, but know all there is to know (I will still see it for myself this weekend), but even so I'm still going to ask: "How does Mutant Fifield enter the Prometheus ship?" The trailer shows a quick glimpse of him in front of an "expendable extra" mechanic. So is the sip already open? Or do they open the ship for Fifield?
And also... how many people does Mutant Fifield kill? I heard it was 3. Is that true?
Oh, and Holloway really asks Vickers to torch him?