There are terminals in every Order Silo. Interacting with the device grants you control of the facility. You don't even need to defeat all enemies. Simply run past them and hack the terminal to complete the task. Order Silos are somewhat akin to Safehouses in that they also act as fast travel points. They have vending machines but no bounty boards. Once activated, a large balloon will fly out of the base. You can use your grapple to zip line and reach higher ledges.