Is this were you are?
"Walk a few steps into the jungle until you get a clear view of the
tower ahead of you. There’s a sniper and a merc with an M4. GET THE
SNIPER FIRST and then the M4 Merc. Run up to the tower (to the left of
it is some ammo), and climb it. Grab the sniper rifle, go to the prone
position, and use your scope for the next camp area. In this next area,
you should see approximately 6-8 in the scope. However from memory, you
will have a little under 20 mercs total in the camp, and just 5 more on
patrol before it in the jungle. To get a clear count of how many mercs
there are, grab your binoculars and ‘tag’ the mercs. Now, grab the
sniper rifle, and snipe the sniper in the opposite end tower. Now look
down at the ground where most of the Mercs seem to be. They seem to be
next to an explosive barrel (the yellow one). You know what to do ;^)
Give or take 10 seconds, an enemy helicopter will fly over to the tower
you are on. As a friendly warning, you have more than enough time to
get off the tower and take cover; however I choose to stay on the tower
as it cannot shoot me from above the sky but only from the sides. Your
P90 is the weapon of choice for taking out the machine gunner in the
chopper while taking cover next to the wooden log that supports the
roof of the tower. Around 10 hits should do the trick. Once the chopper
flies away, leave the tower and head deeper into the jungle following
the yellowish trail."