I like number 2. It looks the most exciting and has some strong perspective elements to it as well as some interesting colour. The others are nice also, but don't have the same vibrance and life to them.
Number 2 also packs a whole lot more visual variety than the others. The stairs, the black panels, the different floors, and the ceiling... the whole image has more going on in terms of texture and structures. I also think it's more balanced as an image. Nice work.