Really? Care to tell everyone the layout of your home? How many feet in your room is your bed? How much storage do you have in your dresser? If someone wanted in and out as quick as possible, what's the best route?
Labs have sensitive areas too. Knowing the layout of them helps not just in-and-out operations but can also guide other kinds of educated guesses. Do lab staff in their offices have direct views of the lab equipment or are they separate? etc