I am very glad that you mentioned this one. It all-too-often gets overlooked in the pantheon of character moments in B5, a quintessential character-based series.G'Kar: "You are right, nothing would have been changed. Except that my people would now be a dead race."
Delenn: "You have come a long way, G'Kar. Further than I would have guessed. Sheridan's promise binds me as well it does him. We will take you into the Council, G'Kar. And someday, when all this is over, perhaps you will find it in your heart to forgive me."
G'Kar: "Perhaps...but not today."
This seen shows Delenn's bravery as well as G'Kar's. Yet it also paints G'Kar in a very sobering moment. Like him, I doubt I'd be able to forgive her in that moment. My head would understand and even agree with her rationale, but my heart would still break at the mere thought of how many lives had been lost. A very raw, emotional moment for sure.