Only, during the respite the absence of his rival afforded him, he reflected, partly on the means of deceiving Mercedes as to the cause of his absence, partly on plans of emigration and abduction, as from time to time he sat sad and motionless on the summit of Cape Pharo, at the spot from whence Marseilles and the Catalans are visible, watching for the apparition of a young and handsome man, who was for him also the messenger of vengeance.

Fernand's mind was made up; he would shoot Dantes, and then kill himself.

But Fernand was mistaken; a man of his disposition never kills himself, for he constantly hopes.
During this time the empire made its last conscription, and every man in France capable of bearing arms rushed to obey the summons of the emperor.

Fernand departed with the rest, bearing with him the terrible thought that while he was away, his rival would perhaps return and marry Mercedes.

Had Fernand really meant to kill himself, he would have done so when he parted from Mercedes.