The Moment When 'Wolfpack' Brother Decided to Escape

— -- A family of nine spent 14 years confined to a cramped New York City apartment under the strict rules of a paranoid father until the day one son found the courage to break free.

“I just thought, ‘You know what? I’ve got to do it today. It’s now or never,’” Mukunda Angulo, now 20, told ABC News’ “20/20.”

Mukunda lived on the 16th floor of a public housing development in New York's Lower East Side with his oldest and only sister Visnu, his brothers Narayana, Govinda, Bhagavan, Krisna (who now goes by Glenn), Jagadesh (who now goes by Eddie), and their parents Oscar and Susanne.

For years, Oscar Angulo, a Hare Krishna devotee from Peru, forbade his children and wife from leaving the apartment and held the front door’s only key. Aside from the few trips outside allowed for appointments or strictly controlled visits to New York tourist destinations, the children had no contact with the outside world.

"He would say to us, ‘So outside there’s good people, and there’s bad people,’” Govinda, 22, told “20/20.” “Dad would always explain, ‘You know, I like to keep you all here, protected, you know, because this is a big city. There’s a lot of crime going on.’”

Watching films and reenacting movie scenes, the one privilege their father allowed, became their one true salvation. Mukunda, a middle child, was the family’s prop master, creating costumes, guns and swords out of whatever he found in their home.

In January 2010, Mukunda, then 15, woke up one morning determined to make his escape.

"It was a Saturday morning, and I don’t know. Something just sparked in me to just do it,” Mukunda said.

He waited for his father to leave the apartment to buy groceries before going to his prop closet and putting on a mask modeled after the one worn by the character Michael Meyers from the movie, “Halloween.” This way, he reasoned, if his father saw him he wouldn’t be recognized.

“I wouldn’t dare do it when he was around,” Mukunda said. “He would catch me, and he would definitely never let me do it again and always keep his eye on me.”

“I was pretty fearful,” Susanne Angulo said. “Not so much for his safety or if he would be OK, but for the repercussions of that.”

Mukunda walked outside, and because he didn’t know his address, he made sure to keep their apartment building in his sight. Still wearing his mask, he went into a bank and a supermarket, terrifying people who saw him. Soon, he was stopped by the police.

“They started asking, ‘Do you live here? Where are you from?’ And I was always taught to never interact with any people, so I didn’t say anything, you know. I didn’t give them any information on me,” Mukunda recalled.

In his first real-life adventure, he was escorted away in an ambulance to Bellevue Hospital Center’s psychiatric ward.

“I was never in an ambulance. I was like, ‘Woah, look at this. This is just like a movie set or something,’” said Mukunda.

Mukunda said the week he spent at the hospital was fun because it was the first time he interacted with people. When he came home, his father was no longer in control.

“He knew it was coming. We all knew the day was coming,” Govinda said.

“I mean, I tell you, having independence feels really great if you have never had independence your whole life,” Mukunda said. “It’s so powerful, you know. You feel like, I can survive.”

After Mukunda’s escape, the boys started going out together, eventually meeting filmmaker Crystal Moselle, who shared their passion for movies. Mukunda and his brothers star in Moselle’s documentary, “The Wolfpack,” which won a Grand Jury prize at the 2015 Sundance Film Festival and premiered in theaters nationwide on June 19.

“A walk on Broome Street" in New York changed everything, said Mukunda.