These yogis are fortunate that they were assisted in regaining objectivity. As you’ve implied before, who knows what their situation would be if babaji hadn’t showed interest in safeguarding them. Posts like these are a grave reminder of the importance of remaining objective whilst we practice meditation. My understanding is that naad serves as an anchor in objectivity. Hence the pressing need to develop and maintain a relationship by focusing and linking with naad day after day during meditation. 

I’ve read many notations of Madhva in the Yoga Invision series of him detailing the love affair between himself and naad. The ups and downs of their relationship, the rejections and the quality of his meditation when they were on good terms. I enjoyed these since they were funny but also enlightening of the importance of maintaining a relationship with naad.