A Q clearance could mean you are privy to absolutely nothing. The janitors cleaning the buildings in the secure part of LANL all have Q clearances because they

A Q clearance could mean you are privy to absolutely nothing. The janitors cleaning the buildings in the secure part of LANL all have Q clearances because they might, might, be exposed to classified information. Needless to say, just because they might poke their nose in the wrong office, doesn't mean they will. The less you know, the less the Lab wants to track your whereabouts after hours.