Not at first.
I don't think I managed to get my point across. Having Lucan see that that his uncle, aunt, and cousin have all been killed and thinking that if he kills Varian, he'll be next in line for the throne is quite a different scenario from having him see that his uncle's double has been killed and even if he kills Varian, Strephon is still out there. After all, Lucan can't count on everybody who knows about the clones having been killed or keeping their mouths shut, nor can he count on Strephon acting like a total idiot. Even the possibility that the man killed could be a double ups the risk he'd run if he kills Varian to a whole other level.
Hans
I see. Ok, interesting point, but it depends on how crazy Lucan is. If Survival Margin has Stephon making comments about Lucan. It's possible to have the Richard III scenario with Lucan. Meaning, Lucan and Dulinor could have betrayed each other. Hence, utter bitter rivalry.
IMTU For example,
"When the deed is done, call for me. I will declare a federation under my rule." Lucan