Mirror in the bathroom
From the NYTBR rave for Tom McCarthy's Remainder:
There's actually a crucial scene in Remainder that reminds me of a different PKD scenario —so much so that I wonder if it's an homage. In PKD's Time Out of Joint, one character goes into a bathroom and reaches for a pull cord instead of reaching, as usual, for the light switch. (I think this actually happened to Dick himself, an inspiration for the book.) This is one of the first indications that all is not right in the suburban 1950s milieu the characters inhabit—it's a small but significant crack in their world...
In Ridley Scott’s dystopic film “Blade Runner” (based on the Philip K. Dick novel “Do Androids Dream of Electric Sheep?”), the title character has the unpleasant job of exterminating “replicants” — bioengineered androids designed not to have advanced emotions. To distinguish replicants from their human counterparts, he subjects them to a test called a “void comp,” meant to expose their inadequate capacity to feel. But an unusually sensitive female replicant suspects the blade runner himself of unnatural callousness. “Did you ever take that test yourself?” she asks him. After reading Tom McCarthy’s novel, you know his narrator would fail the test. But “Remainder” raises another uncomfortable question: How many of us could pass it?
In Remainder, it's a literal crack—in a bathroom, no less—that nags at the befogged narrator, and causes him to embark on his project to re-create a setting from (possibly) his previous life, the one before the mysterious accident that has rendered him rich but confused.