User blog comment:Xilinoc/Ch. 553 - Frozen Cross/@comment-7079377-20131017232010/@comment-5695542-20131018233334

Personally i hope he is dead or at least unable to fight if the latter would then be healed and return later which would be ok but other then that. Remember last chapter (The Fundamental Virulence) Urahana did say the hollow pill would make the bankai's like poison to the Quincys. To me this meant that not only would the bankai return to the owners but those Quincys that had said bankai would be hurt and became weaker only time hence the term poison.

"Kubo does this often, e.g. with Isshin vs White he was cut so he was unable to use his Bankai and with Shinsui against Stark."

Well Isshin was cut on the back near or at one of a soul reapers weak spots (i forget what they are called something like a chain or well not the be confused with the soul chain of a ghosts cheast has he is under going holloifion but think of them like a pressure points on a human) that weak spot being damaged made it impossible of Isshin to release his bankai due to not being able to fully control his power or something like that. Like on a human striking a pressure point would lower the speed/strength of a say arm or just out right temporary paralyzing it.

Shinsui well idk about that but you are likely right here he did say he was about to release it but Unitake stepped in and stopped him later on we did see that Shinsui was easily able to handle Stark in skakai on his own.