After the pistol whipping, you'll find that the UFE are moving through the area. Go back down the stairs and follow the alley way. In the first building you enter will be some pain killers on a bench to the right. As you go to exit, there will be a dead body on the floor and a blood stain on the floor, grab his pistol and check the body for a clue. Go out onto the balcony and make your way down the stairs. You don't have to shoot, just run.
Max will evade the police and you'll find yourself in an alley. Make your way up the alley and out onto a platform. Follow it around until you get another cutscene where you see Giovanna and Mecelo. Continue down these stairs and the next. You'll enter a tunnel and come out to a larger area. You'll hear about the rent-a-thugs. At this point, you'll see a man come up the stairs to your left and get gunned down.
Look in that direction and kill the UFE that killed him. Go over to your recent kill and pick up the rifle that he dropped. Immediately take cover because there's another cop at the bottom of these stairs. Kill him (he has an auto-pistol) to the left and then try and clean up any enemies down below. There will be one on the middle level of the building across the alley. Check under that UFE to find part of the Golden DE .50.
Go down below and take the small alley to the right. Two cops will come up the alley and provide some more ammo. Continue down the alley until you see a man get gunned down. Turn around the corner to the left to kill the people who killed him. There will be two more cops coming up either side of this alley. A Shoot Dodge may help a lot here. Kill them and then inspect the body up at the archway just to the right for a clue.
Go through the archway and up the alley. Make your way through a building with some innocent people. When you come to the woman who runs into her bedroom, check her bathroom floor for a part of the Golden M972. Coming out the other side, you'll see a chopper. Go forward and down the stairs to safety. Inside the next room will be a large window and a group of four UFE across the street. Kill them and vault out the window. Make your way along the ledge and you'll be chased by the chopper. After a moment, you'll do another roof slide and have to take down the chopper. The first part will just be a shootout where you take out the people in the middle of the chopper. After a moment, a man with a rocket will appear. Shoot the rocket to take out the chopper.
When you have control of Max again, make your way down the alley to a point where the UFE are about to execute a man. Kill the three enemies, Examine the dead resident and move further down the alley. Check as you come to the stairs for part of the Golden M972. After you observe the UFE some more, check the brush here to find part of the Golden DE .50. Not far from there, you'll find a nook with the last part of the Golden M972 in it. Head up the long staircase nearby. You'll come to a fence and have to siddle along above the streets. When you get to the other side, you'll find some UFE occupying a bridge ahead.
Kill the two on the bridge and then focus on the two on the balcony across the street. One more enemy will come out of a room on the left and after he's done, the final enemy will come out of a door on the balcony to the right. Cross the bridge and make your way to the left. Drop off the roof and go down the stairs. Do a Shoot Dodge for a nice amount of Bullet Time. You'll get three UFE on the stairs and one on a balcony ahead. Before leaving, check inside the barred porch area to find the last part of the Golden DE .50. Go further down and at the dead end, go through the door on the right.
At this point, you won't regain control of Max until you get in a fight with a man with a big blade. I'm unsure if they always go in the same sequence and if it's the same across systems but the order was: Aim, shoot, pick up, and sprint. Doing this will successfully end the chapter.
