Stairway to...

A couple friends led me up into this tower. The stairwell to get up into it was kind of like the rocket ship slide you might see at city parks. Once we got up in it, we were in this big room with lots of people. Then I realized there was too much weight on our side, and we started to tip, so I asked if we needed to move to the other side to even it out. Someone reassured me it was ok, but I moved over anyway. Next thing I know, the whole tower is tipping to the ground, so I was holding on for dear life, thinking it was the end. We got all the way to the ground, and out the window I saw that the tower was on top of this old tree- it was a huge, sturdy trunk, but multiple swaying branches. After a second, the tower came back up again and tipped down to the other side, and it continued doing this, back and forth, like a pendulum.