The store's interior is actually just a textured cube primitive. Building a detailed 3D interior would've taken bog down the already slow rendering time. In the bottom image, I have created a few of these 'interior cubes' and carefully positioned them within the drugstore to fake the appreance of depth. A slight brightness is applied in the glow channel to give off some lumination. This screenshot was taken from the nighttime version in RDS so just ignore the two bulb lights. I hope this answers any questions you had about the image in particular. :)