Friendly note: I think you want some word other than “vicarious”, which doesn’t make sense in context, the way the sentence is constructed. (I’m not precisely sure what you were trying to say, so I won’t suggest alternate words.)
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!