For an ordinary person, it would have been easy to guess that these machine units might be the central hub controlling the Sky Soldiers.
Nothing else in this city had been preserved so completely. Those machine units had remained operational the entire time, matching perfectly with the Sky Soldiers that had been operating continuously.
But these young people, who had never received an education, would not make that connection.
All their ideas rested on basic knowledge passed down by word of mouth and their own abilities. Their horizons were limited to this ruined city, leaving them utterly unable to consider such a possibility.
After discovering the experimental records concerning the Sky Soldiers, they were merely "shocked" for a moment. Not one of them suggested that the Sky Soldiers' control hub was very likely these machine units.
They chose to continue investigating the equipment in the hangar until they found information deeper within.
Fortunately, they could now operate the equipment for long periods without triggering alarms. This gave them enough time to explore, without being driven out every time and having to sneak back in.
At last, after a long period of exploration, they discovered a special record. In it, the researchers seemed to be adjusting the Sky Soldiers' "behavior."
The Sky Soldier in the experimental footage had initially reacted sluggishly and moved clumsily. But after a while, the image switched to another location, where a mechanical arm used a strange object to touch a nearby machine unit. When the image switched back, the Sky Soldier's movements had suddenly become nimble, as though it had been suddenly enlightened and grown much smarter...
Would actions performed on the "machine unit" be reflected in the "Sky Soldier"?
The young person operating the equipment quickly noticed this footage and watched it over and over