My take on the shelter would be to mirror the current ground-level structure underground, but replace the functional console with another broken one. Then add empty plastic bags, tin cans, cardboard boxes, wrappers and plastic bottles to the lockers to give the “your supplies have run out” feel.
As for the ground level, I would eliminate all of the windows, and three of the entrances. This way the whole structure gets a more “bunker-like” feel, as a symbol, without adding much to its value.