Don't open the door

You checked how solid the walls are... but what about the floor?

You look down an check the floor. There is nothing special about it, it looks like solid concrete. It's probably even sturdier than the walls.

But as you look down, you realise you don't actually have shoes. You've been barefoot the entire time. Why don't you have your shoes ?
And then, you start to wonder : how did you even get here ..?
And who are you ?

You're starting to freak out a little.