User blog comment:Shunsui Kyoraku/Tosen Explosion?/@comment-1489595-20091231073019

Nah...I think Tosen just died. And because he is a hybrid who was sort of still being supported by his resurreccion's power his body just ruptured rather than die cleanly. Aizen's attention was likely drawn to the scene because Komamura was hollering at him.