Anything possible
The first thing I figured out was that everything around was changing constantly. It looked like a regular hospital corridor, yet with bending walls, lamps of many different colors that blinked like broken pedestrian lights... and the absence of exit or entrance doors.
The last of the above circumstances made me feel awkward and ask myself how I got there. A thought ran through my mind: "what if those soft walls can open?" I touched the wall - and soon regretted it.
The corridor formed what looked like an outbranch. I stepped in, and it was the moment I realized that the floor there was also unstable... I fell... Long, long falling.
At the bottom of the soft-walled pit, there was some kind of grass (luckily, it was not nettle!). Perhaps, the lighting had changed while I was falling, because now I saw everything in cold blue-green shades.
A couple of flies flew past me. Apart from the initial feeling of surprise, I think it was the first time I saw living creatures in this strange world.
I stood up carefully and looked around. The bottom area seemed to have stretched and got bigger. I noticed a ladder haging from the ceiling. Yes, an opportunity!
Of course, I was climbing it very cautiously, thinking of a plan. Firstly, I needed to know what food or drinks I could find; secondly, if there were any hostile creatures; finally, most importantly: how to get back?
I got to eat in that world only once, and had better not. It was some kind of berries in an empty hall conquered by bushery. I ate one, and it was sweet. Some minutes after, I consumed the whole bush, only to find out that there were lots of big greasy worms on the lower leaves. I did my best not to vomit.
The last room was the most peculiar. When I stepped, or rather, fell into it, I saw it had both sides ceilings. Let me explain: the floor (or the side I was standing on) was the same as the ceiling with buzzing neon office lamps attached to it.
The final seconds of my being there were pure idiocy; for I suddenly escaping gravity of the "floor" and strong pulling force of the "ceiling". I bumped my head really hard against one of the lamps... and then I woke up in my bed.
You may take my story for a dream, but I actually found small pieces of glass thrown around my room - a kind used in lamps.