It has been some time since I did the GMAT Testing Center Shop(s), but I remember the narratives being pretty straight forward. I just completed 3 MCAT Testing Center Shops, different MSC, and for those there were 4 narratives, 1 after each section: Registration, Security Check, Exam Room Experience and Exit Experience. If I remember correctly the GMAT Report was similiar. There may have been one more or one less narrative. However, they do not ask you for a novel. Just the usual, address all no answers, and maybe give some support for yes answers when appropriate. For example, why did you answer that the exam proctor was professional in there dealings with you?
Lady Marius
Canadian Mystery Shopper