That water/gunfire kind of reminds me of when I played Operation Flashpoint many years back (The original one made by BIS, not the crappy ones made by Codemasters). I played this mission that went for 3 hours. I was near the end of the mission, half dead, and just needed to get to the evacuation point about 3km away. So I took the long way around to avoid any enemies and when i was nearly there I heard gunfire so I immediately hit the deck. Looked around, couldn't see anyone. Got back up and started running again. Heard gunfire again, hit the deck again. This happened about 8 or 9 times until I realised that I ran on to a patch of dirt. The sound of footsteps on dirt sounded like gunfire from far away.