ToME: the Tales of Maj'Eyal

Is the area below the portal in the Sher'tul fortress for putting stuff for storage? Will it disappear if I put it in the fortress, but not in the storage area? Or the only thing that is important is that the storage area automatically sorts items?

For those who look here first rather than the wiki:

https://te4.org/wiki/Sher%27Tul_Fortress

You can leave items anywhere in the fortress without them vanishing; that room just automatically sorts dropped items.