First up I want to say that I am a Christian (Protestant, but not that it matters what kind of Christian you are), and believe in God the Almighty. I also believe that there are "supernatural" entities among us (just read the Bible you would know that from the beginning to the end they are also mentioned in there), and that there are good entities that do God's work, as well as evil ones that do Satan's work.
In Singapore, every able-bodied male has to undergo 2 years of National Service (compulsory conscription), in my time this was 2.5 years. Most of us will end up serving in the Army, and smaller numbers will join the Navy, Air Force, Civil Defense, Police force, etc. I was posted to the Military Police, which is a different branch from the Army. This was almost 2 decades ago.
During BMT (Basic Military Training), I was ill for a couple of days during one of the exercises, and therefore was assigned to be the a part of the OppFor (Opposition Force), which is basically to simulate enemy activity and movement. Most of this involved defense of an objective like a hill or building. And so I was placed deep in the jungle (training area) with a platoon of OppFor, waiting to ambush the unit on their way to the objective.
Setting: About 3-4am in the morning, on a tropical training island called Pulau Tekong, which for hundreds of years prior was a sleepy fishing village, converted into a training island for the military. The area where we were positioned was deep in the jungle, meaning that trees grew close together, with occasional thick undergrowth which was conducive for concealment. The nearest support vehicles (commanders', first aid, etc) were about 1-2 km away on a service road as there wasn't enough space for a vehicle to pass between the vegetation. There was a little illumination from the moon, but as the canopy was thick, it was pretty dark down where we were. It does get quiet in the forest sometimes, depending on whether the animals are making other noises, (crickets, cicadas, frogs, etc), but generally sound doesn't carry far because of the thick vegetation.
After several hours of waiting, my mate and I heard a slamming of a vehicle (sounded like a jeep) door nearby, as though it happened only a few meters away. We slowly turned to look at each other, as if to say "did you hear that?" (we couldn't talk -- to remain tactical). We turned back to observe our arcs-of-fire. Several minutes later, when the phenomenon was wearing off due to our fatigue, "bang" we heard it again. Later after the exercise was over, I confirmed with him that we did indeed hear the same sound twice. There was no vehicle nearby, nor was there any other sounds or movement to suggest that one was nearby (engine sound, footsteps, talking, etc). Besides, no matter how well you can drive, you wouldn't be able to squeeze a car in between the vegetation. As we were only acquaintances (different companies), we didn't have the chance to discuss this again.