The Pitt Episode 12 “6 PM” delves into the absolute horror that is an emergency room during a mass casualty event. We learned last week on the MAX show that there was tragically an active shooter at PittFest. This week, Dr. Robby (Noah Wyle) and his team have to pivot to disaster mode, taking in an avalanche of critical cases with limited resources and even less time to prepare.

When we spoke to The Pitt star Supriya Ganesh last week, she likened the next run of episodes to a “horror film” and revealed that shooting Episode 12 and beyond was so “insane,” she desperately needed fifteen minutes under a weighted blanket each night to recover.

In The Pitt Episode 12 “6 PM,” the doctors and nurses of the fictional Pittsburgh Trauma Medical Hospital transform themselves into a wartime hospital. (Shawn Hatosy‘s Dr. Jack Abbot even returns with literal supplies from his time as an army doc on the front lines!) Current patients are moved to other departments to make space in the ER. A triage station is set up outside to assess every incoming shooting victim in record time. Patients are kept track of with sharpie-penned tags and funneled between various zones with colorful slap bracelets that signal their risk assessment.

While we follow the likes of Dr. Mel King (Taylor Dearden) and Whitaker (Gerran Howell) as they handle the “yellow” cases, the bulk of the drama takes place in “red zone.” That is where patients who need immediate treatment to save their lives wind up. Soon, The Pitt‘s expansive 360° set is overrun with gurneys. Where once one patient was being operated on, now four, five, or even more cases are fit.

“It was insane, to put it lightly,” Supriya Ganesh told DECIDER. “Because I was in the red zone, I’m essentially in a place where there’s a lot of movement happening.”

“When I tell you it was like we were having five separate medical procedures happening simultaneously, and each of those five procedures were happening with medical accuracy, and, like…god love our med techs,” she said. “I mean, they would come and make sure each of the five procedures with each set of actors and extras or whatever was happening to that level of accuracy that we carried throughout the show.”

DECIDER can confirm that the intensity in the Pitt’s ER doesn’t slow down until the season’s end. Meaning that all of the actors had to tackle more basic staging work, plus the emotional labor of re-enacting a mass casualty event.

“It was crazy,” Ganesh said. “I mean, I had a weighted blanket in my dressing room. There were so many times where I would finish my day and just spend like 15 minutes lying under it, just sort of thinking like, ‘Oh my God, that was so intense.’”

Ganesh told DECIDER, though, that was nothing compared to what real emergency room doctors have to deal with. In her research for this part of The Pitt — “Because not to spoil anything, but Samira is kind of hit hard by it,” she teased — she found a doctor who posted about his experience working through a mass shooting.

“He broke down,” Ganesh recalled. “He basically just said, ‘We can’t keep doing this. We can’t keep treating people for this and having this toll on us for things that could easily be prevented. It does not need to be this bad.’”

“So I think that’s the thing I would tease. There’s a lot of breaking down of our protocol, a lot of breaking down of how emergency departments deal with mass casualty incidents. And I think there’s a lot of space given to show just how much it affects the medical team,” she said.

When DECIDER spoke to The Pitt‘s Shabana Azeez this week, she explained that she “found it more overwhelming to do to the research” for this specific story arc.

“Obviously I’m from Australia,” Azeez said. “We had one mass shooting in the ’90s and we melted all the guns in two weeks, which I think is a reasonable response.”

“Our mass casualty is based on the Vegas casualty and so researching that and seeing play by plays of that was horrifying, like that was more intense than anything.”

Azeez went on to give The Pitt credit for “being really sensitive” and “not showing, not glorifying anything, not focusing on the shooter.”

“So actually, it felt like a relatively safe space compared to the things that I saw online,” she said.

Ganesh likewise hoped that audiences would get the message that it doesn’t have to be like this.

“I do have faith that all that hard work and adrenaline rush, I guess, eventually pays off,” she said.