One of the lessons (as if it wasn't clear already from past scandals like Enron and the financial crisis): listen to the low-level people, including the ones who were fired. One or two of them might just be bellyachers with an axe to grind, but when multiple people in a position to know keep pointing out the lack of clothes on the emperor, there's something
wrong. From the NYTimes review:
[former secretary of state and Theranos board member George] Shultz helped his grandson land a job; when the kid reported back that the place was rotten, Grandpa didn’t believe him. There is a larger moral here: The people in the trenches know best. The V.I.P. directors were nectar for investor bees, but they had no relevant expertise.
Even outsiders could have spotted red flags, but averted their eyes as if they wanted to believe. Fishy excuses — Holmes blamed a production delay on an earthquake in Japan — were blithely accepted. When a Walgreens team visited Theranos it pointedly asked for — and was denied — permission to see the lab. A company consultant pleaded that the chain not go ahead with in-store clinics. “Someday this is going to be a black eye,” he predicted. But Walgreens was plagued by a “fear of missing out.” Like many executives, they were looking over their shoulder and not at the evidence.
Of course you have to know about the low level people raising the red flags. That's not easy, even today when sites like glassdoor exist. Which is another reason why real journalism (ie the kind that confirm information and get second sources, not just run with whatever's available for the current news cycle) is more important than ever.