“You can’t beat the story engine,” executive producer Michael Seitzman of CBS’ new medical drama Code Black said of hospital dramas. “People are coming through doors and having the worst day of their lives” to be treated by people who after 13-hour shifts who are supposed to be “at their best. … How do you explore all that in the face of this rolling catastrophe?”

The expression “Code Black,” he explained today at the TCA Summer Press Tour, refers to a situation at trauma hospitals when the influx of patients overwhelms the staff to such a degree they can’t treat patients properly.

code blackDistinguishing his show, Seitzman said, he’s created a world that is “not glossy” and uses a lot of natural lighting. “We do not worry if somebody falls into darkness,” he said. For verisimilitude’s sake, they hired 30 trauma nurses to work both onscreen and off, getting them SAG cards so they can speak lines. “We’re going to fit our drama in and around that” environment, he said.

The show also has used about 600 extras, he said. That includes one who showed up with actual severe bruising, which caused some concern among producers until she confessed she’d had an eye and neck lift and decided that, given how she looked, she would “fit right in.”

“We took a lot of pains to take the technology out of the show,” he said, to distinguish it from the trend these days of making medical shows look very cutting edge, technology-wise and “five minutes into the future.”

BEVERLY HILLS, CA - AUGUST 10:  Actress Marcia Gay Harden speaks onstage during the 'Code Black' panel discussion at the CBS portion of the 2015 Summer TCA Tour at The Beverly Hilton Hotel on August 10, 2015 in Beverly Hills, California.  (Photo by Frederick M. Brown/Getty Images)

The show is exhausting to watch, one reporter said. “I’m exhausted,” said star Marcia Gay Harden. In March, Harden, who originally was cast in the co-starring role of Christa, was recast to play the lead, Leanne, who is the force-of-nature residency director in the ER and originally had been cast with someone two decades younger. Harden volunteered to a reporter today that it’s relevant because when the recasting was under consideration, she did not know if she had the “sexuality” the role needed, though she could bring the gravitas. The producers convinced her otherwise.

Seitzman, she said, “has given us a show that is not snarky. Real, hard core, ugly sometimes — but with values I can so b get behind: family, love. Health, teamwork and making each day a little better. … That is what I was brought up to believe. I get the cutting-edge dramas — love it. But to spend these kind of hours and devote this kind of energy, I do want to be behind those other values.”