User blog comment:Shunsui Kyoraku/Tosen Explosion?/@comment-1454424-20091231081714

Yeah I don't think it was Aizen. Or at least it wasn't Aizen doing anything right then. He might have built some sort of self-destruct sequence into Tosen so that when certain conditions were met Tosen exploded. But I think what happened was that more of his resurreccion disappeared and that caused the explotion. Resurreccions like bankais seem to start to disappear as the person starts to die. Both Starrk and Ulquoirra were changing back as they were dying.

Tosen was clearly dying from the injuries sustained from Hisagi. Instead of going peacefully after seeing Hisagi's face or something like that, Tosen exploded mid-goodbye because most of his resurreccion had disappeared by that stage.

Maybe if Komamura or Hisagi had cast a healing kido on him or something then maybe Tosen wouldn't have died. But for all Komamura's words neither he nor Hisagi moved to save Tosen in anyway. It maybe because they couldn't, i.e. they have no knowledge of healing kido, but most likely they knew it would be a pointless gesture as Tosen would be put to death eventually for his rather considerable crimes.

So for all Komamura's words about not wanting to lose Tosen, it's probably best Tosen exploded. If Tosen had lingered to be executed later... I think that would just have caused Komamura and Hisagi more pain in the long run.