Make your way to the street and take out the enemies. As you turn to the next corner, you'll have to flank the MG using the ledge to the left. Have your partner take the ground path and take the aggro as you move across the ledge to get near the MG. A well-placed grenade throw should be enough to take the gunner out without risking MG fire as you get near. Once the gunner is gone, use the MG and eliminate the incoming enemy waves, including a few RPG troopers. Once cleared, destroy the marked wall on street level using the MG to create a path.
Enter the room then breach the door for a scene. You'll encounter a brute. Just concentrate your fire on it then proceed to the street to fend off several enemy waves. If you have you and your partner's overkill meter filled, this is a good place to activate both to score some double overkill points. More brutes and snipers will take position so take your time eliminating them via Overkill or standard shots.
Continue to the plaza and take out the enemies there. You can use and detonate the stacks of fireworks in the area to deal environmental damage. Be careful of the enemies that will go rushing in from both hallways. Once cleared, make your way way around as more enemies appear, including some brutes. Keep killing enemies until you get the objective to head to the hideout. Follow the path to complete the section.