The prison itself was a huge, sprawling complex which provided ample opportunity for both prisoners and intruders to get lost, confused, and cornered. Generally, the corridors of the base were almost empty (when there was no immediate threat, there was no real need to heavily patrol the halls), though as soon as intruders were detected, or prisoners escaped, the corridors were swarming with groups of stormtroopers and bounty hunters. Because the prison was designed to house Wookiees, the base had a rather heavy garrison. All stormtroopers (and probably the bounty hunters too) had strict orders to set their blasters to stun. The reason for this was very simply; if they started dropping prisoners like flies, there would be a wild, full-scale breakout attempt.