This dream was in first person but to keep it interesting I’ll replace myself with, ohh, let’s say… Burt. Also edited slightly for clarity.
Burt, Frank, Mizzy, Jobe, and Jeff are all in Walmart. Jobe discovers an unmarked door hidden between some of the shelves and dares Jeff to open it. Jeff complies and opens the door to discover a dimly lit carpeted staircase that descends out of sight. Intrigued, they all agree to sneak down to find out where it leads. At the bottom of the stairs they discover a seemingly endless labyrinth of liminal wood paneled office-type hallways and doors. Here’s an AI approximation:

The area is seemingly devoid of people, and all the doors lead to random storage closets, empty offices, conference rooms, etc. The hallways go on forever in an endless series of twists and turns, and the gang splits up Scooby-Doo style to explore. Burt and Frank go down one path, everyone else down another. While looking around, Furt, now joined by Jobe, discover a strange room with around 20 bunk beds with people’s belongings strewn about. Signs of life. Jobe stays to poke around while Frank and Burt continue through the maze. The next door they open reveals a huge basketball court and gym with people working out at the far end. They quickly shut the door and run down the twisting hallways, hoping they weren’t noticed. They eventually come to a dead end with a single door down a short hallway that has a bronze plaque on it labeled PRESIDENT’S TOILET. They open the door to find a tiny, unlit room barely big enough to fit a single toilet. Burt says he has to take a shit, Frank tells him to hurry up. As soon as Burt flushes, an alarm starts blaring throughout the complex and people begin to emerge from some of the rooms and file out in one direction. Frank and Burt follow them nervously and make small talk with them, learning that the alarm means that the president is going to address the members of the complex and they all have to gather outside. On the way they link up with Mizzy and make their way out of the back door of the Walmart, congregating in the loading dock area. As they’re looking around for Jobe and Jeff, another alarm sounds from above. The crowd goes quiet and looks up to a pope-style balcony high above the loading doors. President Jason Goldstriker emerges and begins to address the crowd. “I’m sorry Burt,” he says, “but you flushed the elimination toilet and now you’re going to have to go home.”
(Ok I made that last bit up, I actually woke up as soon as he stepped out) I’ll take my puzzle pieces now, please.