The face-up plane card isn't currently part of its owner's planar deck. If the chaos ability is rolled by the owner of Pools of Becoming, Pools of Becoming is not one of the three cards that are revealed.
Pools of Becoming
You may put the chaos abilities of the three revealed plane cards on the stack in any order. The last one you put on the stack will be the first one to resolve.
The controller of a face-up plane card is the player designated as the "planar controller." Normally, the planar controller is whoever the active player is. However, if the current planar controller would leave the game, instead the next player in turn order that wouldn't leave the game becomes the planar controller, then the old planar controller leaves the game. The new planar controller retains that designation until they leave the game or a different player becomes the active player, whichever comes first.
Magic: The Gathering · ™ & © Wizards of the Coast · Illus. Jason Chan
Card data via Scryfall. Rarix is fan-made; not endorsed by the rights holders.
