 Why was it advantageous to the prisoners to make noise constantly?
She was in a detachment of three unfortunates like herself, convoyed by an irritable guard, climbing the steel steps toward Block O from the floor below, when she heard the yelling. The outside guard pulled the switch that turned on the tanglefoot electronic fields that swamped the floor of the block corridor and of each individual cell. While the fields were on, you could ignore the prisoners—they simply could not move fast enough, against the electronic drag of the field, to do any harm. They had spent so much time in prisons that it was sometimes hard even for them to remember what they really were, outside. The inside guard finished putting the new prisoners away and turned off the tangler field once more.
 It drew attention away from their escape plan.
 It convinced the guards and others that they were crazy, and to leave them alone.  It intimidated new comers like Bradley.  It drew attention away from their escape plan.  It annoyed the guards, and made them go through their routes faster.