She said the system was "designed to make them think they could suffer serious harm" if they didn't perform the services - because they'd handed over damaging collateral to DOS such as nude photos and financial details.
One whistle blower, Frank Parlato, NXIVM's ex-publicist said Mack never had "the ability to be an excellent body servant or valet".
Mack, 36, arrived at a Brooklyn courthouse Monday morning to change her plea on charges of racketeering, extortion and forced labor, reported Page Six.More news: Kirstjen Nielsen to Resign From Department of Homeland Security
Raniere and three co-defendants, including heiress Clare Bronfman and Mack, had pleaded not guilty to conspiracy and other charges. The group heavily attracted women, including a number of high-profile actresses like Mack, her Smallville co-star Kristen Kreuk, and Battlestar Galactica's Nicki Clyne.
According to the Associated Press, Mack wept as she admitted her crimes Monday and told a judge, "I believed Keith Raniere's intentions were to help people, and I was wrong".
Online. "I must take full responsibility for my conduct and that is why I am pleading guilty today".
"I know that I am and will be a better person because of this", she promised.More news: Meghan Markle and Prince Harry host first guest in new their home
The prosecutor's office did not immediately respond to PEOPLE's request for comment. The mother, who was known to NXIVM underlings as the "Prefect", is facing 33 to 41 months in prison at her July 10 sentencing.
With jury selection beginning at the federal case against a cult-like upstate NY group, TV actress Allison Mack pleaded guilty Monday to charges she manipulated women into becoming sex slaves for the group's spiritual leader.
Mack also explained why she was drawn to NXIVM, founded by Keith Raniere, who is charged with sex trafficking and possessing child pornography. Until the Salzmans' guilty pleas, officials and associates had repeatedly denied all wrongdoing and disputed allegations that it is a cult. "This Office and our law enforcement partners are committed to prosecuting predators who victimize others through sex trafficking and forced labor".
Mack had pleaded guilty to the charges against her, along with Russell and Lauren Salzman.More news: Brexit: UK asks European Union for further extension until June 30