I believe this movie is about 10 years old and has a US military base whose commander is conducting some form of medical experiments on soldiers believed dead or missing in action during the Vietnam era. A new soldier assigned here finds the hidden men and befriends one of them. When he questions the others stationed here, he is believed to be making it up or crazy because of the station's solitude. The solitude helps isolate the experiment from discovery.
The mention of the Vietnam era experimentation will conjure ideas of Jacob's Ladder. It is not. This movie was not horror.