After entering the main door, there was a hallway.
Chen Xu looked around. Whether it was the floor, the walls on either side, or the ceiling above, everything was made of the same material, shining with a metallic luster. He asked, "Could it be that this shelter was built entirely out of metal?"
The cylindrical robot replied, "Sir, I'm sorry, but my database does not contain that information."
Chen Xu saw it walk to the wall, tilt its body, and touch something. The door then slowly descended. He asked, "Is that the control for opening and closing the door?"
"Yes. The top is for opening, the bottom for closing, and the middle to pause," the robot explained.
Chen Xu took note and asked, "What should I call you?"
"You can call me 2003," said the cylindrical robot as it waited for the door to close completely before leading the way.
He then noticed the wheels at its base.
The two followed behind it, walking further inside.