1. After killing Valero with your spider, you've become a hunted man.
2. Walk along the rooftop to this open vent.
3. Crawl through the vent and it will collapse. Ready your weapon to take out this patrol immediately upon exiting. Ascend the stairs.
4. You'll need to go right to proceed through the map, but I recommend clearing out the area on the left first.
5. Here's the scene as you pass through the left doorway.
6. Make use of your MAC 10's medium-range capabilities in these dead-end corridors.
7. Once the area is secured, return past the stairway (visible ahead) and pass through the opposite door.
8. Here's what you'll be greeted with.
9. Ascend these stairs.
10. After this firefight, continue up those stairs ahead.
11. Defeat this guard before proceeding through the open window to the roof. Drop to the garden below.
12. Approach your backpack (visible on the ground next to Chaser) to initiate this cutscene. Grab your bag and proceed down this opening.
13. Open this grate.
14. Follow the vent to this room, seen earlier.
15. Activate this switch to load the next area and end the level.