This week, we hear some shocking insights from a former Theranos lab director who says he tried to stop the train before it ran off the tracks. From failing machines to a lack of proficiency testing, he tells of the pressure he felt to vouch for tests while maintaining his integrity as a lab director. And he describes how he says he tried to delay the Walgreens launch, pleading with a "nervous" Elizabeth, who went forward nonetheless. But does an aggressive and lengthy cross-examination undermine his claims?

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