What mood did Orwell create before writing about Julia and Winston’s capture in 1984?

As the scene progress closer to the place where they are captured, the mood increases in ominous undertones.
Winston spends a great deal of time just prior to the capture reading Goldstein's book. In it, he ponders the Thought Police, his government's necessity of DOUBLETHINK, and how people are controlled by insanity.
He dozes with Julia and then wakes to a song being sung from below: "It was only an ‘opeless fancy." The hopelessness of Winston's own situation is becoming more clear. Julia awakens and discovers that the oil is out in their stove, and she is sure that she filled it. The ominous undercurrent becomes stronger as the reader realizes that this fantasy the two have created cannot last forever. The song from below picks up again: "They sye you can always forget." This line points both to the way the government erases history and foreshadows the events to come for Winston and Julia. The two embrace, Winston notes that he and Julia can never have children, and the two recall a song that they once heard together. Thinking of it, they each say, "We are the dead," which seals the mood and finalizes their futures as the walls speak to them, noting their crimes, and the house is surrounded with government workers to claim them.