Well, then warden's hp goes to zero, you need push one button (left mouse click, by default).Oh? The way Azellz described it in another thread, i believed the "instant kill" version to have no QTE. What's the "one hit" version?
In "instant kill" version warden will be dead after this.
In "one hit" you need push one more button from WASD.
How disable all QTE, like in training room? I don't know. But, in training room specials wardens, not the same as ordinary - maybe QTE depend on this.