Renton in “Memento Mori”

I want to know. Wasn't there a way for you not to have to kill him? (about Charles) Holland: Charles was a member of the SOF, just like Eureka and I and Ray, too. Renton: Why does Ray hate Eureka so much? Holland: Charles and Ray always wanted to start a family, but Ray was unable to bear children. Renton: Huh? Holland: and Ray believes that the reason why she can't lies with Eureka. Even if it costs me my life, I'm going to protect the two of you, but if something happens to me, I's trusting you with Eureka. You were the one she chose. Earlier, you asked why it was I killed Charles? Because we're both the type of people that don't know any other way. The same can be said for Ray.