Relative to the level of the ramp, the airside spaces of PIK are basically below ground level (built that way to avoid the jet blast of early jets). There are still a few open air courtyard spaces with neglected plants in them, but they're no longer accessible to passengers. Otherwise it's a pretty dingy place - natural light through a few skylights help, but not being able to see outside is psychologically not good for any building occupant. There was, for example, some compelling research done (IIRC) at the University of Sheffield about ten years ago that proved to the NHS that patients get better quicker (and therefore occupy hospital beds for less time) if they have a view out of the building. Ideally that view should be out onto a street, car pack, service yard - anything that lets them see the day to day routines of life passing by.