User blog comment:Gon10/Kuchiki Byakuya´s Bankai/@comment-8669536-20130621094711/@comment-11051098-20130623124830

If Komamura gets the damage anyway, despite who uses his Bankai, Yhwach could just make Bambietta release his Bankai and destroy it, killing him, anytime he wanted to. If he found out about the close connection between Komamura and his Bankai.