User blog comment:Xilinoc/Ch. 585 - The Headless Star 4/@comment-24153155-20140618145221/@comment-24153155-20140619110625

I think it would be a major flaw if the Royal Guard, being charged with the protection of the Royal Palace (among other duties), is not aware of the exits and entrances to the Palace. It is understandable from that perspective that any interaction between the Royal Guard and the Seireitei is limited, and also that only 4 Shinigami were allowed entrance to the Palace. I think it all is part of a strategy from the Royal Palace, although I can't imagine exactly right now why it would be those 4 being the ones (I guess Ichigo must have been anticipated), and not any of the others.

The King's Key clothing issue made me wonder why Shutara materialized a staircase for Ichigo. If the clothing he wears protects against the friction caused by traveling through the portal, I think it would be logical to state that Ichigo and co. were at least able to travel at the same speed as the descending staircase, and perhaps the staircase functions as some sort of beacon: it guides the traveler through the (72) barriers back to the Seireitei. I think that the Shiba canon just acts as a catalyst, very similar to the rocket fuel in human-world space craft launches. There must be something about the Bleach General Relativity ;)