With this setup, even if the United States figured out something was wrong, cracked the numeric riddle left by Yang Qi, and found the canyon where he actually stayed, they wouldn't know where Yan Fei and Yang Qi had gone. Yan Fei was now a hundred kilometers away from that canyon, and this area was so desolate and secluded that without any clues, it would take those people at least several days to find the hiding place of Yan Fei. With this time as a cushion, Yan Fei would have already taken Yang Qi back to Misty Island.
To save Energy Points, the Drone was hovering within that white cloud. However, the fierce gales at altitude made the cloud drift all around, and in order not to be discovered, the Drone had to move along with the cloud's drift. As a result, the consumption of Energy Points inadvertently increased quite a bit. Yet it was precisely because of the drone's "eyes" and "ears" that Yan Fei could detect any movements around him even while hiding in the cave.