The real demon
The soldiers truly had been soldiers before, and had even collaborated with the Midnight Battalion various times. On this that they had previously taken to calling the Cursed Planet, rather than its official name of BGY-987, their entire unit was positioned close to the battalion. That is why, when they were originally given the order to retreat, they took a path close to them.
When catastrophe struck, and the ships were destroyed, they were the first to spot the battalion's beacon. Fortunately, due to their close proximity, they arrived unharmed and without incident. Unfortunately, while the remainder of their companions were normal, at some point during the original retreat they had been separated from their group.