With pratyahara, you turn into investigating your brain, discovering your deeper layers of consciousness, clearing the mind unbothered by the desires and speaking the truth. This picture can’t be accessed from the logical, reasoning level of the brain which you experience in consciousness, but more from the intuitive and creative levels, when your non-dominant hemisphere gets activated and slower brain waves, present in a deep sleep, span across your head.
Sense withdrawal also helps to get in control of your senses, to get free from distractions and concentrate on the things that you are supposed to do, not letting the things you are not supposed to do to take over your mind. Sense withdrawal is a training, a formal practice, which takes time to achieve mastery over. As you learn how to perform your job well through repetition, you can also learn how to control your senses well.