But it was just too ugly.
The Demon Rats for the first time in this entire expedition, risked their lives entirely to see what was beyond the walls even though the Demon Horde and the System had the technology to know what was in all those areas. It was a confirmation survival test for the Demon Rats too since the System did promise some system points as a reward to be able to learn and act without the power of the System.
"More barricades in the city and into there's two sets of walls within the Inner Quarters too!" The Demon Rat scout reported after struggling with much effort just to have a peek at the top of the outer walls. It knew while it was currently using the mobility gear it had to reach its peak, there would be a moment when it would have to descend. And that was when the living breathing fortress wall of Ends would bring its prey with its tentacles into the belly of the monster. (In fact, the entire wall is its belly)