Did Adam really shoot Doug?
I do think it's very possible that Adam shot Doug, but I do slightly wonder if Doug would have mentioned that to Nina since he was still alive when she came over and found him.
Also, how fast must that van have got out of there after Adam shot Doug to not be seen or heard by Nina as she ran over?
Doug might not have wanted to mention that Adam shot him because that would cause a huge ripple effect or something, but it just seems Nina (being an agent) should have been able to notice that he didn't shoot himself.
I only say what I mean and mean what I say.