There was a second room where they led the inspectors with true lab eqpt while the other had the inaccurate machines (according to the book)

Are you sure it wasn't the other way around?

Weren't they pretending to operate their own equipment while the real equipment was 'behind the curtain' ?

Depends on what's being audited. For investors, you want to show a room of gear that other companies don't have. For certification of medical equipment, you want to demonstrate that your process works.

Yeah, that's what I remember too. They had the Siemens equipment in a back room that they used to run the real tests on, but pretended that they were using their own tech for these tests.

Maybe I forgot, but I think they were operating both.

BioCurious received some very nice lab equipment for free when Theranos shutdown: https://biocurious.org/