At the beginning of the movie Rex is playing a Buzz Lightyear game. Go to the part, in the game, where Buzz enters a well watched door. He goes around a corner, then it goes to Zurg looking at radar map of the place, if you look at the map you can see that there was no corner for Buzz to go around but is heading toward a corner.
Yes there was! When Buzz drops down the big circle thing and the top closes in like a Z shape, he turns on his glow-in-the-dark thing. Now this is the part where the animators messed up-in that circle thing was a corner to turn into the main hall. Go into a circular room, scale it, and you'll find you'll have to turn to go from either side unless you were in front of the way out.