Floor Zero

Mark was the last one to leave the office building. He stepped into the elevator and pressed -3 for the parking garage. The doors slid open to a dense, misty primeval jungle. Terrified, he slammed the 'Close' button and pressed 1. This time, the doors revealed a bustling medieval marketplace. Desperately trying to find his own era, he kept mashing different buttons. Eventually, the doors opened to a quiet diner from decades ago. He spotted a young couple nervously chatting in a booth. Recognizing them, he walked over, chatted briefly, and offered the young man a cigarette. But when Mark stepped back into the elevator, the entire panel of buttons had vanished. Only a single, dead button remained: '0'.