Start with taking 26.Tag lying in the street on your right. When you get to the locked door, wait for Jack to open it. You'll get attacked by Drones and Wretches. Move back to the street you came from and finish all enemies off shooting from the hip. After you get rid of all enemies, two Boomers will get out of a hole in the wall. If you have a sniper gun - shoot their heads off, if not - take cover and shot everything you've got at them. Boomers will charge forward all the time so it's best to take your position in the alley you came in from.
There's a conservatory behind the door. You're safe...till you run into a Berserker. Be sure to grab a Hammer on your way- you'll need it to finish the Berserker off. You'll meet your enemy in a big greenhouse. You can't destroy him in the place you're in, so run towards the hallway the Berserker came from. You'll find yourself in another big greenhouse. What you need to do is to provoke the Berserker into doing as much damage to his surroundings as possible. The bigger part of the ceiling gets crushed, the more place you have to use the Hammer. The fastest method to kill this enemy is to use the weapon after destroying the first pillar, a split-second after he goes into the next greenhouse. When it's over, use the handle at the end of the room to extinguish the fire.
If you still have that Hammer, making your way forward should be a piece of cake. If you don't - well, you'll need to do your best with what you have at hand. Hammer can be really helpful when it comes to closing enemy-spawning holes. Should a need for more firepower arise, you can use the Troika gun. Next courtyard - you'll fight mostly Drones here. Watch out for those who jump down from the crumbling wall and attack from the back. After you get rid of the Drones a Boomer will appear. Take cover, and finish him off. You'll run into another Boomer near the barricade - he's got some support but a few grenades will make them history.