Why does Gardo interrupt Olivia's narration of the jail visit with his own narration in Part 3, Chapter 6?

Gardo interrupts Olivia's telling of the events in order to tell Olivia how sorry he is for deceiving her. He says that he had felt that he and Raphael and Rat could not trust anyone outside of their tiny circle. He appears to be sincerely sorry for lying to Olivia about the purpose of his visit to Colva Prison, particularly after he sees how confused she is when she figures out that Gabriel Olondriz is a complete stranger to Gardo, rather than being his grandfather, as Gardo had told Olivia to convince her to accompany him to the prison.