Skimming over the excerpt (I haven't gotten that far in the book), it seems to be omitted, which makes sense given that the excerpt focuses on the company's corporate dysfunction. I have to admire Carreyrou's and his WSJ editors' restraint in not reporting such a salacious detail during the course of their Theranos investigation, because a case could be made that Holmes's and Balwani's relationship is germane to how Theranos turned out.

> In early August 2007, Ed accompanied Elizabeth to Nashville. Sunny picked them up from the office in his Porsche and drove them to the airport. It was the first time Ed met him in person. The extent of their age gap suddenly became apparent. Sunny looked to be in his early forties, nearly twenty years older than Elizabeth. There was also a cold, businesslike dynamic to their relationship. When they parted at the airport, Sunny didn’t say “Goodbye” or “Have a nice trip.” Instead, he barked, “Now go make some money!”

Or maybe, perhaps the damning evidence against Theranos was so voluminous that the Holmes+Balwani relationship was small potatoes in comparison and not worth the newsprint.

edit: The WSJ recently published an excerpt of the book's chapter devoted to Balwani. Here's the Twitter link (WSJ paywall seems to let in twitter.com referral domain): https://twitter.com/JohnCarreyrou/status/997522528301174784