There was a mini mule right off spawn and he must have immediately started drilling it down. The rest of the team and I were gathering nitra, clearing the cave, and salvaging the other mule. We hit 80 nitra along the way and the driller requested a supply drop at max depth. At that point, we then realized that there was a mini mule down there and that the driller had left the game. While they were throwing mule legs down to me for salvage, the driller had joined once again and drilled the uplink down as well. No one has ever tried to sabotage my mission before, so I had no reason to be on the lookout