It seems as if this passage is about shipwreck divers:
Shipwreck interiors can be terrifying places, collections of spaces in which order has fractured and linearity bent until human beings no longer fit.
Here's what I was thinking when I read those words:
Pop history can be a terrifying collection of spaces in which primary order has fractured and historic linearity bent until human beings no longer fit.
The shipwreck diver tries to imagine the original form of the ship before entering the wreck. The primary researcher surveys the wreck of pop history for surviving outlines of historic truth that can be used as starting points in primary research ... starting points for reconstructing the true form of events.
How is deep sea wreck diving like primary research? Like this:
Raking leaves or watching a Giants football game or walking the grocery's dairy aisle, Chatterton stitched together his experiences on the Doria, and gradually his eyes adjusted, until the quilt of separate experiences aboard the shipwreck formed a single picture in his mind. "This is why I dive," he told Nagle. "This is what I want diving to be."