The more I look at this image, the more puzzled I get. It almost seems like the rear wall is not straight to begin with, it appears to be two walls that have a shallow angle at 3 columns of shelves from the left. Hard to say for sure though, since we do not have enough detail info, nor do we have enough/any tiles to work on.
The perceived distortion in purely due to the projection used, in combination with viewing the image from too far away (which is almost unavoidable with such a wide angle).
Cheers,
Bart