I am not sure what page 162 is in your book, but I assume that you are asking about why Granger is crying after the city has been bombed. I would say that he is crying because he is emotionally overcome by the bombing of the city.
I think there are two reasons why he is overcome. First, he has to feel for all the millions of people who have just died. I think it is this emotion that has him swearing as well. Second, he may be thinking that after all this time wandering, he will be able to go back into society. Maybe he and his friends will be able to change society now. That has to be an emotional thing.