In a scene cut from “Lies My Parents Told Me”, Giles confesses to Buffy that he killed Ben.
BUFFY: “Exactly. The First’s doing this. Spike’s innocent.”
Giles pauses a moment, then:
GILES: “So was Ben.”
Buffy stops cold. The Vamp launches at her and she WHIP-STAKES him to DUST.
GILES: (with difficulty) “He was a human being, after all. Forced, his whole life, to share his mortal form with a demi-god from a hell-dimension.”
BUFFY: “Glory. I know. What does that have to do—”
GILES: “Ben was oblivious to the atrocities Glory committed. No more responsible for her crimes than Spike is to his, when triggered.”
SLOW PUSH IN as he continues…
GILES: (cont’d) “Glory was invincible, impossible to kill… Ben was not. So after you defeated her. After you left Ben lying there. Alive. I made a decision. One that you couldn’t.”
GILES: “I put my hand over his mouth. And as he struggled, weakly… I smothered him. Because it had to be done. (looks at Buffy) He was a liability.”
Buffy’s eyes go wide as she starts to put it together.
BUFFY: “Oh god… You’ve been stalling me. Keeping me away—”
GILES: “Buffy, it’s time to stop playing the role of a general and start being one.”