In Abattoir after you've extinguished all guards in the land mine field (5 Total; one on the ground, Two in the tower, and two on the balcony on the far side of the field), and "diffused" the land mines just in front of the gaurd tower there are some "treats".
If you climb on top of the stack of 8 barrels and run/jump towards the tower, you will grab on to the ledge. the just shimmy to your left, around to the opening on the end so that you can pull yourself up. (this took me a few tries) Inside you will find 2 cartidges of 5.56mm ammo for your SK-20, a med kit, 2 flares, and a frag granade.
I found it I only had a pinch of life left absolutely no bullets in either gun, and had not killed the second granade throwing sniper in the tower, and had already made it to the satellite tower save spot. There was no way I was going to make it any further so I then started goofing around.
I doubled back and launched a sticky cam at the sniper only to completely miss and land inside the room on the tower. Rotating the cam around... Eureeka! Gold mine (or at it seemed so from my current life status). So I used a distraction Cam and smoked him out. Approximatley half an hour later I figured out how to get up there.
When you have just reached the stairway with the broken bit at the top and the guards in the room.
kill the guard with his back to you and then shoot out the camera or jam it!
The guard should walk ova 2wards the camera and can b killed easily. drag both bodies into the big dark corner to the left of the door! continue round the right corner and into the door straight ahead.
Creep in and collect the medkit and ammo! turn back around and head out the door u came in.
continue down the hall 2 the door with a code, the code is 1436 and walk through slowly. a turret is on ur right which can b beaten and turned off with a well timed run.
Now shoot out every light on the walls and chandelires on the top level. climb up on2 the ledge with the pots by the door u came throught and turn it off iff! 2 guards shud come and b killed. now turn it off!
Climb across the flag pole behind u slowly. whack on ur heat goggles and stop halfway. 2 guards shud come across, 1 will let the otha guard through as only he can get through the eye scanner.
Wait 4 them 2 both go away then continue across. go right and turn off the turret gun. go back along the pole and grab the guy who opens the door.
Drag him across and make him open it!
this is much easier than the otha way, u will save a considerable amount of health