This is page 42 from Book of Pages. The policeman who arrested Jiriki earlier on in the book spots him sitting outside the bookshop and attempts to surprise him with a shriek grenade.
One ancient truth which technology has always been unable to allow for is the incalculable ineptitude of some of its users. Take, for example, a simple device like a hammer — no complicated user interface there, no abstract conceptual model of its operation, no instruction manual to ignore — and think “thumb”.
Unfortunately, as technology advances, the risks associated with it advance step for step in equal measure. From hammers to nuclear power stations; from thumbs to populations. And people are aware of this: they coined the term “failsafe” and built it into some of the systems they were nervous about.
But what failsafe really means here is humanproof. With a little reflection, it seems as if machines are trying to communicate something profound back to their creators: the failsafe part of any system is where the machine knows and acts better than its operator. Failsafe means that, when it really matters, the humans can be stopped from meddling.
And there, of course, is the problem. The humility of being controlled by your own creation is one which humankind is not willing to tolerate. So from the minds that brought you “failsafe” comes “override”, and people, thumbs and all, are back at risk. You use a machine and suffer the consequences. You try to launch an intimidating shriek-grenade with the safety plug still in the end of your barrel, and your equipment will explode.