[Though he had hoped to simplify matters between them, 9S quickly comes to suspect that he's only muddied the waters further. He thought that in pointing out that both of them had a hand in their circumstances, to one degree or another, that he might lessen the severity of 2B's guilt. Instead, it seems to him that he has achieved nothing better than making her feel even worse.

And this is a perfect illustration of all that he had been so determined to avoid by keeping the truth to himself. He regrets that it ever became necessary to tell her, and that he allowed himself to get frustrated enough to think something that would concern and upset Jude enough that inevitably he'll ask about it. Historically, he always goes to 2B with his concerns about him. And so, it all comes back to his own failure to reign in his thoughts.

That is, of course, a weakness shared by every Scanner unit]

Still, I made a choice. And I think...I had more of a chance to do so than you did.

[Not by much, confined as they were by their roles as YoRHa units, but he was in some ways better about taking independent action. What he dealt with weren't orders issued to him but rather ones that concerned him, those that 2B hadn't much choice in carrying out. But she had given him a choice. He could have released her from a role that pained her greatly. Instead, he ended himself. That was the easier option for him, and not her.

9S can't quite claim that he regrets it, because it would be a lie. He's good at pretending, but omission is his main vehicle of dishonesty, rather than outright falsehoods. Given the choice, he knows he's selfish enough to kill himself rather than her again, because the thought of being without her is far too painful]

I'm not the only one who hurt because of how things were. And I think it'd be wrong to ignore that.