Nrama: It's interesting that Superman has to hurt himself with Kryptonite before he can heal.
Pak: Yeah, it's this sacrifice that Superman made. He basically let himself be killed off in order to try to save the day.
In this article from just last month, its writer explains that Bruce Wayne has to let himself be killed off in Batman #49 in order to become Batman again to try to save the day.
Initially, Bruce says that by regaining the memories, he could be a Batman without the trauma. Yet when they learn that Bruce would have to go brain dead before being able to receive the memories, the truth comes out. He could never be both. He could never be the happy, well adjusted man that he was during his amnesia and the same watchful protector of Gotham that the city needs him to be. And so he willingly traded his happiness for obsession to once again save his city.
What's next? Sacrificing the entire DCU so that it can have rebirth as new hero...?!