Why would you say "vicarious" doesn't make sense in that context? It IS a second-hand account.
vicarious: "experienced in the imagination through the feelings or actions of another person" - synonyms: indirect, second-hand
vicarious: "experienced in the imagination through the feelings or actions of another person" - synonyms: indirect, second-hand
I don’t want to put words in his mouth, but I think he might have been trying to say that the author’s description was so vivid that he could vicariously experience the jury process through reading it.
Sorry for the pedantry!