In the excerpt, the speaker compares the experience of being in a brightly lit room to the sudden shock of darkness when the light goes out. This vivid imagery evokes a sense of loss or disorientation, highlighting how quickly things can change from comfort to uncertainty.
The moment the light turns off symbolizes the abrupt shift in perception or reality, illustrating how familiar surroundings can become alien and unsettling. This powerful metaphor sets the tone for themes of change and disconnection present in Harold Pinter's "No Man's Land."