I'm not sure it's best to cut out the atrium like this as a building inner. It's tricky because it is open air on the NE end, but completely covered by a clear roof and still contains escalators and ground, level 1, level 2 walkways around the outer ring of the atrium and overall I'd consider it still "inside" and part of the building.

I think we either

1. map the N/S buildings separately as building=retail then use building=roof for the atrium, or
2. map the whole thing as one building=retail (without an inner), then use building:part's within it to model the 3D void of the atrium.

I think (2) is probably best and models what's on the ground best.

We should probably also move the shop=mall attributes to another way especially since some of the shops are within https://www.openstreetmap.org/way/550340851 but still part of the mall.