Act 2: Nightfall - 6. The Heart of Darkness
Go through the building and kick open the door and be ready for two Drones (I used my Longshot here since I was low on ammo). Shoot the tank behind a pillar and run to where the Drones were, then run to through the archway and get to the small slab with a Frag in hand. Aim through the other arch and get a Frag in that hole; should be told whether you hit. Then snipe the remainder. Shoot the tank from where you stand, then go over there, and find the tiny clip of ammo behind the tank (a bit back). Proceed.
*Be mindful of where the dark spots are, I found even tiny spots count.
Run to the mailbox across from the car to get a sight on the tank. From the safety of this tank look for another one behind some rubble. Go out and locate the spotlight. Go up the building, grab the ammo, and take control of the light.
*You may notice the COG Tag to the left, but hold off.
Aim it to Dom. Your job, if you don't know, is to follow his movement with the light. So do so and be patient when he takes a while. Wait for him to turn on the pretty lights, then put the light on the COG tag near the starting point. Be ready for the few Wretches on the way down.
With the light on the Tag, go pick up COG # 17.
Some ammo where Dom found the lightswitch. Assist Dom if two Drones are in the area. Get a Frag in hand and go up the street. Enter the building and go into the room so you can get a spot on the hole. Lob a Frag. The Kryll will kill the Drones who try to rush, and you can handle the rest. Shoot the tank from this position and proceed. Don't miss the tiny clip in this room too.
Go up and meet the colorful yocal, the jerkwad.