Compare "There was nothing for Decoud but to remain on the island."
The chapter has already compared Charles Gould and Decoud in terms of their reactions
to seeing the "cruel futility of things." While Decoud's reaction is
an ultimate withdrawal from the fray, Charles Gould's is presented here: though
deprived of any moral basis for his actions, he will go on acting, as a moral
automaton. Or rather as a "buccaneer," i.e., in the name of sheer selfish
gain without regard to morality, as the next paragraph makes clear.