Fred Burton and Scott Stewart at Stratfor provide interesting background for the well-planned and executed Sarposa prison break:
The prison was very old and its mud brick and rock-and-mortar construction was not designed to withstand a serious military attack. Even with some of the recent upgrades to its guard towers, the facility was incapable of withstanding the explosion of an 1,800 kilogram VBIED in close proximity to its front gate. In fact, few facilities in the United States could withstand such an attack, but U.S. facilities typically have concentric rings of security that must be breached in order to get to the main gate. The Sarposa prison is located right on the street and did not have much room to provide standoff space or for such concentric rings.