The small American base camp depicted is set in heavy jungle terrain without the ability to see it's own perimeters. This would be fine if this was during WWII in the Pacific, to hide from Japanese aircraft. But in Vietnam the jungle would have been cleared with "kill zones" in place for camp defenders. Outer and inner multiple barbed wire fences would be around the perimeter of the camp. This defensive construction strategy would prevent such a surprise invasion attack as portrayed in the film.