After leaving the Sewers you will find a seemingly abandoned Construction site. Run around the left side to find a Save Symbol on an oil drum. When you are ready, enter the doors of the house.
There are two Health Drinks in this hall. Follow the hall to the end and go through the door to find a stairwell. All the floors are cut off, so you’ll have to enter on the Fifth Floor.
Go to the end of the hall and through the door. There will be a box of Handgun Bullets on a coffee table box to the left of the mattress, and a Health Drink will be on a box to the right of the mattress. Investigate the filthy mattress and drop it into the hole, but don’t drop down just yet!
Before dropping down the hole, check the wall near the entry to this room. The camera will focus on one section of the wall as you walk past it. Investigate this spot and you will be informed it appears weak. Whack it with a melee weapon and it will crumble revealing the Silencer.
Now walk off the edge and into the hole to the Fourth Floor.
There won’t be anything on this floor, and the door won’t open up. Exit out of a hole in the wall to head outside. There are Pendulums in this section, so be careful. Head around the building until the camera angle shifts and go through that window into the Hilltop Center.