There’s just one point: Cz’s book is going to be published, and many people will see it—he definitely knows that.

And since the book also talks about matters involving a third person, I think he will be cautious, at the very least taking responsibility for the truthfulness.
So I don’t believe he would write about something that doesn’t exist, because there’s absolutely no need to give himself trouble.
So, I have no doubt about the truthfulness of the incident in which Li Lin was reported by Nurse Xu.