bier, coffin
匛 centers on a container for the dead: a bier or coffin used in funeral rites.
匛 combines the enclosure 匚 (box) with 久, likely suggesting a container associated with the dead. The exact historical development is uncertain.
The outer 匚 is a box, and inside is 久, which looks like a person lying down. Picture a box holding a body: a coffin or bier.
For キュウ, imagine a coffin being carried in a quiet, solemn queue: queue -> キュウ, and the box holds the deceased.