In chapters 32 to 33 of "Great Expectations," what happens when Pip and Estella drive by the prison?What are their reactions? And why are they...

Having parents who were sent to debtors' prison and having spent time there himself, Dickens often writes into his narratives scenes that express his repulsion for them.  Also, since he perceived society as a type of prison and deplored many of the conditions existant in Victorian England, Charles Dickens wished to expose these conditions to his readers.

In addition, the prison/criminal motif runs throughout "Great Expectations."  On the marshes as a child, Pip often heard the canon of the Hulk; of course, he encounters prisoners there on the marshes and helps one rid himself of the leg irons with a file. At Mr. Jaggers's residence he meets Molly who serves the young gentlemen their dinners. Thus, Pip's visit to this prison carries the motif through the narrative as well as foreshadowing more encounters of Pip with criminals.

In Chapter 32 Pip arrives in London in order to pick up Estella at the coach, for she is arriving in order to be in Richmond where she will live with a wealthy woman.  When Pip stops to visit Wemmick, Mr. Jaggers's clerk informs him that he is on his way to the infamous Newgate prison where Mr. Jaggers has been hired by a robber.  When Pip asks if the man is guilty, Wemmick replies, "Bless your soul and body, no....But he is accused of it."  Here Dickens suggests again the injustice of the legal system in England, a common motif of his. 

As Pip and Wemmick traverse the dusty, grimy prison, Pip likens Wemmick's walking among the inmates as a gardener in a conservatory walking up and down, tending plants and removing those that are dying--like the Colonel sentenced to die on Monday.  Once out of the prison, Pip feels contaminated and wishes he had not gone as he thinks of the beautiful Estella whom he soon will meet:

So contaminated did I feel, remembering who was coming, that the coach came quickly after all, and I was not yet free from the soiling consciousness of Mr. Wemmick's conservatory when I saw her face at the coach window and her hand waving to me.

Then, in great situational irony, Pip remarks,

What was the nameless shadow which again in that one instant had passed?

Of course, the irony is that Pip believes Estella to be above reproach in name and reputation when, in actuality, she is the child of two criminals herself, and, thus, no true lady.  But, in the opening lines of the next chapter, to Pip, Estella seems more delicately beautiful than ever before with an even more winning manner.  After they dine, Pip and Estella near Newgate. When Estella asks what place this is and Pip replies, she shudders and remarks, "Wretches."  Yet, as they near a sudden glare from a gaslight, Pip has that inexplicable feeing that he experienced in Chapter 32.  However, he shakes it off as he takes her to Richmond and bids good-bye.