Turn around and go backwards from the starting point to find a hidden path which will lead to some Japanese soldiers and a ledge that the first bridge (on the normal path), crosses. If you look down, you will see some soldiers down at the
river (on a dock) that you can kill. There are some vines at the ledge that you can swing on to get access to a tunnel that contains more soldiers and a Japanese machine gun. The tunnel ends at the ledge that is directly after the first bridge (on the normal path). Note: Before swinging on the vines, search the area for a nearby film canister. When you are on the first set of train tracks, immediately after the water tower is a hidden passage.