The worst case scenario is described in this chapter as something that is a rumor to the Gorosei… You read the chapter right? You saw the panel after that where they tell the CP0 guy that they are trying to prevent something that is a rumor REGARDING LUFFY… Right?
how many things in recent memory have been described as rumors by the Gorosei?
Listen buddy, Luffy has been fighting for a very long time, they never ever feared he would Awaken
He fought Crocodile, Lucci, Moria, Impel Down, Marineford, Kuma, Doflamingo, Big Mom Pirates ... etc
And yet WG never mentioned this Scenario where Luffy Awakens
What they are afraid of is Kaidou & his DF
Worst Case Scenario is "Kaidou's Death" which would trigger something Catastrophic
His DF is extremely important, it made him have a Life Time Debt for Big Mom
CP-0 said that they hope Vegapunk's Artificial DF is truly a Failure cuz it would shake the World if it's not
Momo who is Hyped to be the one to start the Dawn ate same DF as Kaidou
Where did Kaidou eat his? It was in God's Valley, the same place where Rocks Pirates, Roger Pirates & Celestial Dragons met
Can't you see that this Arc has been building up for a Mind Blowing Reveal about Kaidou's DF?
U really think that it's just a DF to create Clouds & Breath Fire?
CP-0 were prepared in case Kaidou loses in first place
Lucci brought an entire Army in case Luffy wins, so they are not really afraid if Luffy proves to be too strong
However they also said "We doubt Kaidou loses"
But now, they are starting to have doubts & they are afraid of what might happen to Kaidou's DF if he dies
That's why they are asking CP-0 to help Kaidou kill Luffy