Immediately after Parker pops Capek's nano-tech shield (during an intermission sequence), you will follow a trail. When you reach the area where a dead guard is on the ground, look to the right. Note the small hole where it looks as though a small animal could fit through. Get an explosive and blow a hole big enough to fit through. Enter it to reach a room. Jump to the center then jump up and down to get a fuel canister and fusion rocket launcher.
When you enter the room immediately after you use the jet to transport Gryphon go to the center room you will see a huge Modulation Droid. Run and dodge the bullets and missiles. Look around the room to find ladders all around leading to the top of the ceiling. Climb the ladders and get to the top. Then, look around to find boxes all around. Go to the boxes and walk into each of them on every side. You will get a lot of ammunition, health, and Enviro-suit repair kits. This should prepare you for the Modulation Droid.
When you take the elevator down to Level 17, stop on the second ladder. Climb upwards slightly higher than the room below. Look to your right, and you will see a tunnel. Jump in and proceed through it. You will find a section of little cliffs in which you can get a sniper rifle and an assault rifle.
