When Equality 7-2521 is sent to the Palace of Corrective Detention for his failure to come home on time, he is whipped and placed in solitary confinement. He refuses to speak his secret to the men who have punished him. The reason he decides to escape is explained in the following passage:
It was easy to escape from the Palace of Corrective Detention. The locks are old on the doors and there are no guards about. There is no reason to have guards, for men have never defied the Council so far as to escape from whatever place they were ordered to be.
No one has ever tried to escape for several reasons. First, they are scared, but they also don't know that they can escape. There really is nowhere for them to go and even if there were a place to go, they wouldn't feel safe there. When Equality 7-2521 gets to the Uncharted Forest, he assumes that he is doomed. He says,
Whatever days are left to us, we shall spend them alone. And we have heard of the corruption to be found in solitude.
The people of the World Society are so brainwashed that they don't have the will to escape. They don't even understand the word "escape." Interestingly, this begs the question, why would they need a "Palace of Corrective Detention" in the first place? It could possibly be that they know the system has to fail at certain points, like it did with Equality 7-2521.
There is no need for strong locks and guards at the Palace of Corrective Detention because the people in Equality's society have been brainwashed to follow the rules completely.
It was easy to escape from the Palace of Corrective Detention...There is no reason to have guards, for men have never defied the Councils so far as to escape from whatever place they were ordered to be.
These words spoken by Equality in chapter VI of the text illustrate that if someone were to even end up in a cell, which is very rare, they still would be so enmeshed in their society's concepts of order that they wouldn't think to try to open the door. They would just do as they were told and wait.
Prisoners never try to escape from the Palace of Corrective Detention because none of them dare defy the authorities by planning to evade their fate. This is despite the fact that the locks to the Palace of Corrective Detention are worn out and thus, can be broken rather easily. In addition to that, there are no guards keeping watch on the prisoners making a successful escape even more viable. This indicates that the people are devoted adherents of the system as dictated by the Council. They strongly believe that going against what has been prescribed by the Council would be detrimental to the entire society and so choose to comply with all rules. However, this is not surprising since from a tender age, people are forbidden from independent thinking much less thinking at all.