Perpetual light in the bunkers is a symbol of the unbroken power of the mysterious forces behind the women’s imprisonment. When the women are in captivity, the lights enforce sleeping and waking hours by shifting from full to partial brightness. The women, therefore, achieve rebellion by keeping their own time, independent of the lights. However, there is never an absence of light, just as there is never a moment when the guards are not watching. After their escape, the narrator’s first experience of total darkness in the wilderness signifies her freedom from the cage.

Still, as the women search the outside world for explanations of their captivity or signs of civilization, they only find more prisons. Each has perpetual light, symbolizing the continued power of the system. Outside, the women find neither answers nor a return to their past lives. Moreover, they never discover a power station or conductors, meaning they never understand the source of the electricity—nor the authoritarian forces governing their lives.

The protagonist’s underground home, however, has a light switch. This represents the relative degree of freedom she achieves by finding meaning, purpose, and pleasure amid the desolation. Still, she can always hear the bunker’s air conditioning system.