How does Lemony Snicket use imagery in The Reptile Room?

Example of Imagery:

“It is like walking up the stairs to your bedroom in the dark, and thinking there is one more stair than there is. Your foot falls down, through the air, and there is a sickly moment of dark surprise as you try to readjust the way you thought of things. The Baudelaire orphans were crying not only for their Uncle Monty, but for their own parents, and this dark and curious feeling of falling that accompanies every great loss.”