Question

In the excerpt below, a character experiences a sudden change in his environment:

"For three months, Lionel had lived within the precise geometry of the winter garden—a glass-paneled dome where the heat was regulated to the degree, and the orchids grew in obedient, labeled rows. Here, the air smelled faintly of damp peat and warm iron, a manufactured tropicality that kept the frost at bay but offered no room for wind. He had grown accustomed to its predictable warmth, finding a quiet, numbing comfort in its boundaries. But when the heavy iron doors were finally unlocked in early April, and he stepped onto the open ridge of the northern terrace, the change was violent. The wind, smelling of wet slate and melted snow, struck his face like a physical blow. The sky above was not the safe, cross-hatched glass he had known, but an immense, grey vault that seemed to pull the breath from his lungs. Looking down at the wild valley below, where the pines bent under the force of the gale, Lionel felt a sudden, dizzying expansion within his chest—a sensation that was half terror and half relief, as if the walls of his own mind had suddenly collapsed outward."

How does the shift in setting from the winter garden to the northern terrace function to depict Lionel’s internal state?