Juan rescues Ruby and Sapphire after the explosion at Sootopolis and brings them to Mirage Island, noting a strange fluctuation in time as he does so. He has them train in tag battles against Tate and Liza. He also has them train their minds, secretly intended to teach them how to control the Blue and Red Jewels. Juan conceals from them the fact that they have absorbed the Blue and Red Jewels, but he admits it and congratulates Ruby when he confronts Juan with his suspicions.
The training continues, and when time synchronizes with the rest of the world, Juan sends them back to Sootopolis. He watches the following battle using the water screen his Kingdra makes. When he sees Ruby's Celebi, he realizes that Celebi caused the anomaly in time when Ruby traveled to and from Mirage Island.
Kingdra can use a water screen like a portal to show happenings in other parts of the world.
Juan and Wallace are never seen to interact, but Juan comments that Ruby has Wallace's good taste.