Keating, doing something bizarrely moral that contrasts with his shmoozy ways, says he doesn't want her to introduce him to Toohey since he doesn't want to use Katie to further his career.
Meanwhile Cameron yells at Roark a lot and tries to convince him to quit.
Roark essentially says that he's destined to be an architect, come hell or high water.
Cameron says Roark's life will be super-tough, since society doesn't appreciate geniuses. And Roark, presumably, is a genius-caliber architect.