As you walk through the ruins of the city, you peek a wall and find an army of combine turrets. You also see a combine Turret-Android girl leading the army of regular turrets. She looks as if she had the firepower to mow down a whole army of humans without breaking a sweat.

TG: "You! Human! If you come out now and peacefully, we won't open fire on you, otherwise, we have no choice."