Normally, one is only conscious of the room around one, but when no-one else is present, one's awareness is free to fill all the space.
The quote suggests that in solitude, an individual’s awareness expands beyond the immediate confines of their environment. Typically, one is attuned only to their surroundings, but without the presence of others, thoughts and perceptions can stretch into the entirety of the space, creating a sense of freedom and openness.
This insight emphasizes the profound nature of being alone, allowing for deeper reflection and a broader mental landscape. It highlights how solitude can enhance one's awareness, leading to a unique experience of the world that is often overshadowed by social interactions.