On the throne is Geta (Joseph Quinn), who sits alongside his sniveling brother, Caracalla (Fred Hechinger). The heart of this Rome, of course, is the Coliseum, where throngs cheer for the gladiators who fight and die. There, the ageless Scott remains remarkably at home. The arena, with its eruptions of spectacle and violence, is a stand in for the director’s own vision of the big screen: Go big or go home.