The Bab was insane

Following the Tribunal, the matter of the Báb’s sanity was raised, and a conditional death sentence was issued pending a confirmation of the Báb’s sanity. Dr. William Cormick, the crown prince’s physician, and two Persian physicians were instructed to examine the Báb and determine “whether he was of sane mind or merely a madman.” In his recollections of his visit to the Báb in the Tabríz citadel, Dr. Cormick wrote:

"He only once deigned to answer me on my saying that I was not a Musulman and was willing to know something about his religion, as I might perhaps be inclined to adopt it. He regarded me very intently on my saying this, and replied that he had no doubt of all Europeans coming over to his religion. Our report to the Shah at that time was of a nature to spare his life." (Qtd. in Amanat, Resurrection 391)

The “of a nature to save his life” carried within it the implicit assumption that the Báb was insane.

https://bahai-library.com/pdf/w/woodman_metaphor_language_revelation.pdf

Edward Browne also brings this is his book "Materials for the Study of the Babi Religion".