I think i know now...
you built an opposite model under the tiles, and made the tiles transparent?
Bright kid.
Yep, this is how it works, If you go to Gallary and that thread at the top Solid started, after a few tens of pages you'll find mirror art, quiet wonderful really.
As long as you have the oppositing bricks, the image should be perfect. You are unable to make a player in it, unless its a leveled mirror on the wall, and a duplicated room on the other side, for things like that, you'd have a window to the exact duplicate build on the other side, which will act like its reflecting the room, just make sure both sides are the same, and you should be good.