@Indoor fauna and flora
SCIRE had several zoos and other cultivated forms of fauna and flora. I would argue this was not only part of the entertainment system, but also worked as "green lungs" of the whole arcology. Just as in nature, oxygen production and carbondioxide reduction is necessary for a closed eco-system to remain habitable for humans. You can do all that by means of expensive technology or supplement your technology by plants and animals. The arcology was energetically independent due to its fusion reactors. So an artificial day-night cycle for plants and animals was no problem.
The same goes for ponds, brooks (or even creeks) and waterfalls. They help the filtration of waste water, supply fresh water to fish farms and influence the atmosphere of the arcology. A three-story waterfall will move tremdous amounts of nearby air and help to cool itdown, acting as a heat-sink and remoistering the surrounding air at the same time.