I.e., he saved himself from destruction by clinging to the implement of destruction.
One feels that Charles Gould is deriving a a kind of moral lesson from this, something
like, "instead of protesting the hostile universe, and being drowned, embrace
its hostility and be saved." Though Gould has the wrong image of Decoud drowning
in mind, this functions as yet another contrast between the two men in their reactions
to disillusionment.