(e) If the balloon goes up, the situation suddenly becomes serious or unpleasant. In the altogether is reference to being naked. Hence, bath tub suits. The halcyon days means "good old days". Therefore, it could be reference to childhood. The real McCoy is the real thing and not a copy of something similar Darjeeling Tea is known for its authenticity and purity. To throw down the gauntlet is to challenge someone. But the UN peace keeping force focuses on maintaining peace. Hence, this relation does not hold.