Babylon 5, S05E02: The Very Long Night of Londo Mollari, @29:53
G'Kar: To the Narn Homeword, of course. You came with ships, and guns, and mass drivers. You plucked asteroids out of near orbit and sent them plunging down onto our cities, killing men and women and children. Onto the sick and the infirm and the innocent.
Londo Molari: It was not my idea. I didn't even know. It was Refa. It was not my fault. I said ...
G'Kar: You said nothing. You said Nothing. You said NOTHING. Nothing.
Londo Molari: Leave me alone.
G'Kar: No. Look at me.
Londo Molari: I can't.
G'Kar: LOOK AT ME.
G'Kar: Do you remember this place?
Londo Molari: Yes.
G'Kar: I was tortured in this place. I as whipped. Emperor Cartasia wanted to hear me scream.
Londo Molari: Yes, and if you did not scream, the 40th stroke of the whip would kill you. And your people would be slaves forever. Yes.
G'Kar: You remember.
Londo Molari: Yes.
G'Kar: You were there.
Londo Molari: Yes!
G'Kar: And you said ...nothing.
Emperor Cartasia: Thirty four. Thirty five. Thirty six.
G'Kar: Nothing.
Emperor Cartasia: Thirty seven. Thirty eight.
G'Kar: Nothing!
Emperor Cartasia: Thirty nine.
G'Kar: AAAAAAAAAAAHHHHHHHHHHH!!!!
G'Kar: One word, Molarri. One word was all that was required of you.
Londo Molari: It would not have mattered. It wouldn't have changed anything. It would not have stopped.
G'Kar: You're wrong, Mollari. Whether it was me or my world, whether it was a total stranger, or your worst enemy.
YOU WERE A WITNESS!
IT DOESN'T MATTER IF THEY'D STOP!
IT DOESN'T MATTER IF THEY'D LISTEN!
YOU HAD AN OBLIGATION TO SPEAK OUT!!!
Londo Molari: I couldn't.
G'Kar: And that's why you don't deserve to be Emperor. And that's why you don't deserve to live.