After Toni confirmed that she was one lock away from entering the safe, she decided to split up to go search for the intruder.
Toni didn't come back for a while, which agrivated Cole and he was forced to send Endo to find her and Tchen. After Tchen was inadvertently killed and Endo was knocked out by Sydney, Michael and Sydney encountered Toni, who took them hostage. They managed to subdue her, but at the last second, she revealed that she was an undercover agent for British SIS. Michael and Sydney decided to let Toni keep her cover.
Toni returned to Cole and found him threatening to shoot Arvin should he not give him the code for the vault. Arvin refused and Cole took out his gun. Suddenly, he jerked his arm to his right and shot Toni several times in the chest. Toni was killed because the Arvin and Cole got into a heated arguement, and Toni kept on telling Cole that it's time to go, and the safe has been cracked open. Cole lost his temper and shot Toni several times.