It won't be Clark's time feeling the desire to kill, but actually doing it... there's only one time he may have taken a life directly, and he's still not sure if he did or not.

He can't stumble in Ed's memory-body, more a passenger than a pilot, no matter how strange it feels. Nor can he look away from this man - this creature - that Ed calls Greed.

Better me than Ed, Clark tells himself, though he's not sure how true that might be.