Fight against 10 waves of towers and power generators on a time limit, without a checkpoint. You stay on a large map, the generators spawn at random places, and towers you didn't destroy won't disappear by themselves at the beginning of the next wave. So try to keep the number of towers down, otherwise it will overwhelm you later on. The ETAs on the tactical map help you to stay within the time limit. Although this mission is available after level 6, it gets easier once you have finished the main campaign and have unlocked all abilities and vehicles.
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