Before I was a wave clerk I worked in the warehouse itself and I had applied for a few other positions within. I had been given opportunities to prove my worth and responsibility and thought I had done so well. Afterward the positions were given to people who I believe may have been favored for less than the traits I stated I had been showing. I had to show my frustration with my superior before finally getting a chance at another position which also had been given to someone else who quit two weeks later which only then was the position handed to me.
If you have the urge to move up in the company, I would say its not impossible but there will almost certainly be someone chosen over you or before you.