i'll be honest i was completely surprised when gin took action on aizen, because i though he'd be loyal to him forever, but gin explained it pretty well. he's the only person who knows his weakness therefore the only one to stop or kill aizen is gin! though i doubt aizen is really dead. if he is then thatd be some poor editing on tite kubos part because if this is the end of aizen then ichigo would be traning and fighting for nothing. my guess is that gin though he killed him, but in all reality he just made him weaker to a high degree. but i guess we'll the truth know by next thursday