Nostromo has rejected exploitative allegiance to the rulers. Nevertheless, he needs to make his fortune in the world somehow, and the only alternative he has is "to part in anger," i.e., declare openly his revolt against society. Such a move would not be "prudent" (especially if we read "his companion" to be the Devil). The allegory of the People progressing toward socialism continues: they realize that they cannot make an open breach, but as yet they do not know how they can rejoin society on any basis other than their hateful former fidelity.