Babylon 5 Season 4 Episode 1

Delenn: The stories we've heard about what happened at Z'Ha'Dum. Are they true?
Vorlon Ambassador: Yes.
Delenn: What do you intend to do about them?
Vorlon Ambassador: Nothing.
Delenn: But if Sheridan is still alive, if there's even a chance.
Vorlon Ambassador: Irrelevant.
Delenn: Irrelevant? How can you say that? You know how much depends on him.
Vorlon Ambassador: He has opened an unexpected door. We do now what must be done now. His purpose has been fulfilled.
Delenn: You have the power to send a force to investigate. If he's alive, he can be rescued.
Vorlon Ambassador: No one returns from Z'Ha'Dum.
Delenn: That's what we thought about Anna Sheridan! You were wrong then, you could be wrong now. Are you afraid to admit that you are capable of another mistake? He's bled for you, worked for you, for me, for everyone here. If you turn away now, if you abandon him to die on Z'Ha'Dum, I will have no more respect left for you. Do you understand me?
Vorlon Ambassador: Respect is irrelevant.