is so scared of losing/losing out that he resorts to extreme measures to avoid so.
Extreme measures could be ridiculous, unnecessary, unethical or downright illegal. Say a man who camped for 3 days for his Ipad, which is ridiculous. Or a politician who spies on his opponent for an upcoming election which is illegal like what Nixon did. Or n incumbent politician who resorts to bribing voters while suppressing the opposition parties.
I can accept idioms or British, American and Australian slangs, if any.
I am a newbie here.
I know an English proverb describing this situation: "All is fair in love and war".
I need something to describe the person, who's scared of losing.
They'll stop at nothing