The Dream Magic Experiment

I was in a school or building, 2nd or 3rd floor. It was a sunny day. We noticed that the nearby river is starting to rise. I ran like hell immediately, but others didn't seem to understand that it's about to flood. I told everyone to run as well, but I think I was the only one to leave. Everyone else didn't know better.

The water suddenly retreated, and next came the heavy rain. The sunny sky suddenly turned gray. I was running along a path that looked like a dried-up river. Then in front of me, I saw water rolling in like a wave from the sea. I was in a playground by then. I thought it's too low. There's a set of cube blocks forming a pyramid near a building. I climbed up. I found there are two people (kids? teens?) up there, holding each other to keep warm. I held tightly to them to keep warm as well. They didn't seem to mind.