Act 3: Belly of the Beast - 6. Last Defense of the Locust

The ammo crate up ahead will fill you up. Pull out the Longshot and swap it for the Torquebow by the corpse nearby. Proceed and anticipate some intense action up ahead. To be honest, you may want the Longshot anyway.

The new enemy is called a Theron Guard. They are basically upgraded Drones, so know that. Try to get aligned with the first ramp before the Guards get into position. Use your long-range weapon to pick off enemies. When the first four or so go down, go up the ramp and try to sneak up on the distracted enemies as they attack the other group. About three Guards and three Grenadiers by my estimates, so have fun. When the smoke clears go push the button and you're off (press Y to find it).