"Harry Potter, do you know what unicorn blood is used for?"
"No," said Harry, startled by the odd question. "We've only used the horn and tail hair in Potions."
"That is because it is a monstrous thing, to slay a unicorn," said Firenze. "Only one who has nothing to lose, and everything to gain, would commit such a crime. The blood of a unicorn will keep you alive, even if you are an inch from death, but at a terrible price. You have slain something pure and defenseless to save yourself, and you will have but a half-life, a cursed life, from the moment the blood touches your lips." (Harry Potter and the Sorcerer's Stone)
Is the bold part the short form of ‘one who has everything to gain’?