The player survives the blast to the surprise of Minerva, who decides to try and rescue the player if they manage to reach the surface before the satellite recharges for a second blast. The plasma strike has heavily damaged the installation, and headcrabs now roam free throughout the base, infecting Combine Soldiers. The zombies soon become the primary enemies. Many platforms and hallways are blocked or structurally damaged and require the player to break their way through or find a whole new route around. While making their way upwards the player has to solve some environmental puzzles (like blowing a hole in the floor using gas pipes, while fending off an unlimited number of zombies with reprogrammed Combine Turrets). Upon reaching the surface (now at dusk), the player battles through waves of Fast Zombies, and heads out to the Combine Watchtower, where he makes one last stand against a Combine Gunship, which is preventing the evacuation helicopter from approaching the island. Once the Gunship is destroyed, the evacuation helicopter arrives. The player safely flies off, as another plasma strike annihilates the island.