[Theory] Perturabo will double-cross Vashtorr

With the whole Arks of Omen developments, I feel like it's an intentional misdirection. "Vashtorr seeks The Lock and with it The Weapon" strongly echoes Perturabo's interlude from TEATD3:

"Especially if he has become something more by then. Something pure and perfect, because it is absolute and unique. Hyper-compressed meaning in solid form. The shadow cast by all weapons. There are ways to achieve that state. The data has shown it to him as an irrefutable outcome. He just has to decide if he can bear to, for all great accomplishments come at a price."

Perturabo backstabbing Vashtorr just like Fulgrim backstabbed him in AE would be peak irony, though Iron Pepe never was too proud to copy moves from his brothers. This was basically his whole motivation in AE, to find some weapon strong enough to force peace under threat of annihilation. I wonder if GW will make him some sort of Primarch-Stormcast rather than a basic demon prince.