Wesker gave Ada assignments to deal with people in the area, including Luis Sera and Leon S. Kennedy. Luis was a contact of theirs, and he was making attempts from inside the cult to steal the Control Plaga sample. Wesker made it important for Ada to watch over Luis, but he was soon killed by Saddler, and the retrieved sample was lost. Wesker was not concerned, simply saying "There will be another time...", and didn't pity Luis. Wesker also saw Leon as an extra obstacle and ordered Ada to kill him, though she insisted he was of no trouble. She was quite reluctant to carry out Wesker's order, as she had formed a bond with Leon in Raccoon City. When Wesker later asked if she had gotten a chance to kill him, she lied and said the opportunity had not come. Wesker decided to let Leon live for the time being and allowed him to serve as further distraction for Saddler's followers. He later informed Ada of the Illuminados' panic due to Leon's actions, and decided to have Krauser kill Leon instead. Ada saved him, not playing by Wesker's rules.
Ada falsely reported Krauser was dead to Wesker, who found it interesting how easily Leon could avoid death. This implies that Wesker was suspicious of Ada and quite aware that she had let Leon live, and that Krauser was alive as well. He decided to let Leon take care of Saddler himself, and told Ada to eliminate either one still standing when the fight ended. He reminded Ada that he was running the show, and required her to put a halt to whoever could stall their plans, including Leon. Krauser himself was later killed for real by Ada, who said that she didn't want to fill out a large amount of paper work should Krauser return alive. Ada later helped Leon destroy Saddler and stole the sample without killing him, though Wesker may have been aware of this. It was revealed that Ada was not at all loyal to Wesker, but still to the Organization, whom Wesker had gone against. She sent him a false Control Plaga sample on their orders (actually a Modified Subordinate Plaga), and brought them the real sample.
This, however, only stalled Wesker's plans temporarily. Tricell still compensated Wesker greatly for the different sample he provided, as they managed to put it to use. Wesker left the Organization shortly afterwards, apparently no longer needing them. Ever since his faked death, Wesker managed to hide himself in the shadows flawlessly, and it was no trouble for him to avoid his vengeful superiors.