After crawling out of the narrow cave passage, Schiller landed in a vast hall. The walls were riddled with countless branching tunnels. This Underground Cave was far larger than they had imagined.
Schiller guessed that this was probably the main reason Siltec had chosen the little village as its base. It was practically perfect for evading searches. Unless someone had lived and moved around here for years, no one would ever find where the laboratory was hidden.
"Which passage should we take?" Schiller asked.
Bruce looked as though he wanted to suggest looking for Batman's trail, but if Batman had not come through this narrow passage, then he might not have passed through any of these tunnels either, and naturally would not have left any traces.
Schiller walked over to inspect the passages. They were all pitch-black inside, and he could not make out what lay beyond.
"I have a suggestion," Bruce said. "I spent some time in caves like these before. Generally speaking, we can determine which route leads outside by the direction of the wind, but I don't feel any airflow here. Maybe we can rely on sound."
"Sound?"
"Sound echoes through structures like this according to certain patterns. We can shout into each passage and listen to the echoes to roughly judge the size of the space inside."
"You're not some bat that gained sentience, are you?" Greed said half-jokingly. But he knew that Battleworld Batman's base had also been this kind of cave, and Bruce had indeed lived there for some time. It was only natural that he had experience.
Before they could try it, a strange tremor came from overhead, followed by a droning "Buzzz—"
The noise was so loud and distinct that they did not need to listen closely to tell it seemed to