Geothermal Valley - Entering the Occupied Village (Part 1)

When you're ready to move on, swim through the swamp to the north. Follow the Survival Instinct beacon if you get disoriented.

As you swim up behind the first Trinity soldier stationed at the edge of the clearing, the other man will move off to the left, and you'll see the Melee icon above the first man's head.

Press Y/F to drag him into the water and drown him.

Then climb out of the water and move into the bushes...

...so the 4 nearby enemies don't see you.

There's plenty of cover here: more bushes, a small shed you can climb on top of, etc. By all means, improvise, but here's a strategy that worked consistently for me. Start by moving through the bushes to a position behind the wooden shack on the right.

If you peer around the corner, you can see the enemy on the far right. When he glows yellow in Survival Instinct, meaning he's far enough from other enemies that his death won't be noticed...

...kill him with a silent headshot.