OK, heres my opinion on the matter. As I have said before, I believe that everyone that we have seen in the series from the other world are either evil or atleast only out for themselves, except for the angel in the train car of course, I believe that she is the only one we have seen from the White Lodge. I believe that The Giant, LMFAP, and The One Armed Man are all helping Cooper because BOB is getting too powerful for the lodge to contain and they have to stop him. In FWWM, you will remember the LMFAP saying "With this ring, I thee wed." I believe that by taking the ring, Laura accepts the LMFAP's proposal, and that she becomes his and BOB cannot posses her anymore, which is why BOB must kill her now. Laura knows that by accepting the LMFAP's proposal that BOB is going to kill her, but that he will not be able to feed on her pain and suffering, the LMFAP will inherit that because they are married. Now youre asking "If the LMFAP is evil also, why does she care who gets her pain and suffering?" Because LMFAP didn't torture her for years, BOB did. The One Armed Man does not rescue her from Leland/BOB not because he is unable to, but because he doesnt want to, he wants her to die, his job now is to go to the railroad car and drop of the ring to complete the marriage.