"why does Mike go back to Vietnam to find Nick?"

Rating: Null/10 (9 December 2014)

I think that Mike went back for Nick because of the promise that Mike made him. Right after the wedding Nick had Mike promise him not to leave him in Vietnam, to bring him back home. After jumping out of the helicopter Mike got separated from Nick and hadn't seen him until the Russian roulette place in Saigon, but he was still unable to reach Nick, so Mike left him. After Mike returned home he was just eaten up by his guilt at leaving Nick behind. So much so that he refused to be with the woman that he loves because she had been dating Nick. So, the only thing that Mike felt was left for him to do was return to Vietnam and bring Nick home, even though that meant returning to the place that he most hated and feared. Then, after going through all of that Nick was so traumatized that he just ended up killing himself. But Mike made sure that he kept his promise to Nick, he brought his body back home to the place that he used to love.