Military commanders in Oklahoma were warned this week of a possible shooting at the theatrical release of the upcoming Joker movie after the FBI discovered “disturbing and very specific chatter in the dark web.”

The U.S. Army confirmed the warning to Gizmodo on Tuesday after social media postings by suspected incels (involuntary celibates) were uncovered by the FBI.

In a September 18th email, service members were “instructed to remain aware of their surroundings and identify two escape routes when entering theaters.”

“Run if you can,” the memo read. “If you’re stuck, hide (also known as ‘sheltering in place’), and stay quiet. If a shooter finds you, fight with whatever you can.”

An Army Spokesperson told the outlet: “We do this routinely because the safety and security of our workforce are paramount. We want our workforce to be prepared and diligent on personal safety both inside the workplace and out.”

The threat of violence also evokes memories of the 2012 mass shooting at a movie theater in Aurora, Colorado, during a screening of the film Batman: Dark Knight Rises, where the Joker character was a gun-wielding criminal mastermind.

The upcoming Joker film has been criticized by the relatives of those killed in a 2012 mass shooting, who wrote to Warner Bros. demanding that the company make a donation to charities supporting victims of gun violence.

“We are calling on you to be a part of the growing chorus of corporate leaders who understand that they have a social responsibility to keep us all safe,” the Survivors Empowered group wrote in a letter to company CEO Ann Sarnoff.