In chapter 11 “Dozmary Mine” of Alex Rider Stormbreaker, written by Anthony Horowitz, Alex went to the Port Tallon libary. The librarian told him that his uncle wanted to read a book on computer viruses and a book on Cornwall history. When he studied the book he realized that the diagram matched the map his uncle had left and that there was a mine under Sayle Enterprises. Alex went to the store and bought supplies and headed to the mine to explore it.
Alex, a professional spy can also do sometimes mistakes, because he is also only a human.
He came to a tangle of iron and wire: some sort of machine, long ago buried and forgotten. He climbed over it too quickly, cutting his leg on a piece of jagged metal. He stood still for a few seconds, forcing himself to slow down. He knew he musn’t panic. He forced himself to think. If you panic, you’ll get lost. (P.156)
I like this scene, because I see in that that also a professional spy can make mistakes and everybody is not doing always everything perfect.