I don't think you have to sit there holding a button for 15 minutes!! you prolly only have to hold the button for a few seconds, then work on defending because the enemy will definitely start retaliating. Whoever does the FAQ questions on the main site is basically saying that you hack a base and gain control. Then it will be 15 minutes that you have to defend until the base actually switches sides. It only prolly takes a very short amount of time to switch control, but defending is another matter. This is just what I was able to make sense of out of the main site's FAQ ----> ("Any base Complex can be captured. Base capture can be accomplished by infiltrating or invading a building and getting to it's Control Console. A player can then hack the subsystems of the Console, subverting its routines and taking control of the building. Control must be kept for some time before the building will actually change sides".)
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EDIT: I didn't even read all of this topic, too long. This has already prolly been said.