Counter Terrorist Achievement
Infect all Safe Zones
After the first mission you will learn to "cleanse" terrorist safehouse, the same safehouses Nick uses in the story. There are 8 total, in the same spots as the main campaign, and you need to walk up to an exterior vent and tap to use the larvae bioweapon you picked up from the helicopter crash site, turning the safe house icon from green to red. Enjoy the screams of pain and terror from within the safehouses once you use the bioweapon!
Make sure you finish this before going to the Mayor's mansion to avoid another playthrough.