A prison decides to renovate its showers

An ageing prison facility is constantly beset by long queues for the shower area, which the managers decide to do something about because having all the prisoners together in one area outside of their cells might get nasty. So they look into the problem, and realise that, although the showers themselves are fast enough, the prisoners actually spend a suspiciously long amount of time drying themselves - causing another possible security threat. The managers then hit on the idea of installing a sort of drying cubicle next to the shower, where each prisoner would enter, be assailed by strong blasts of air from all directions, and be fully dry within half a minute, thus leaving them with no excuse to loiter in the shower.

So they install these drying boxes for the prisoners, and at first they seem to be a great success. However, although the machines worked, they were so powerful that they caused a lot of noise, even from outside of the boxes, and - this is important - the noise could be heard in the managers' offices. So the managers decided to find another solution, and remove the drying machines, because they couldn't do any work with that cacophony happening every evening.

When the technician eventually arrives at the prison to remove the machines, he seems rather reluctant for some reason, but the managers insist he does the deed. However, the moment they are disconnected, there's a massive electricity failure throughout the entire complex, leading to all the prisoners escaping due to lack of electric security systems.

Of course, the managers are outraged, and start shouting at the technician: "What the hell did you do? I told you to remove those damn drying boxes, not let all the inmates escape!"

The technician says, calmly, "I thought you knew what would happen if those drying machines were removed..."

This does nothing to assuage the managers' anger, and they keep demanding an explanation as to why they should have know that there would be a power cut. After several minutes of argument, they finally get one.

"Don't you remember?", says the technician. "The mighty con drier is the powerhouse of the cell..."