In this week's installment of "Code Black," the Angels Memorial Hospital staff will be taken off site, as they deal with a catastrophic traffic pileup.

The promo for the first season's eleventh episode, "Black Tag," shows the residents scrambling to save dozens of critically injured people. The crew must face the grim reality that not everyone will be able to survive.

"You want us to decide who lives and dies?" one resident asks ER director Dr. Leanne Rorish (Marcia Gay Harden).

"Decide whose life you can save," Leanne replies.

The preview also shows a young boy who begs for someone to save his mother, and in a dark turn of events, an armed man who demands help for his wife at gunpoint.

The episode promises to be another intense, fast-paced chapter of the new series, which has started to garner a lot of attention from viewers. While the show debuted to average ratings and reviews, numbers have steadily risen since then.

Last month, Deadline reported that CBS ordered five more episodes of the medical drama, bringing its freshman season to a total of 18 installments. This likely means fans can look forward to at least one more season of Dr. Leanne and the Angels Memorial residents.

Much of the show's success may be due to its inspiration. "Code Black" is loosely based on a documentary by director and doctor Ryan McGarry, showcasing the trials and tribulations of an understaffed and often overwhelmed ER in Los Angeles.

"We've been placed in this awkward position," McGarry said of emergency room residents in an interview with Los Angeles Daily News. "You wait forever for us, and when we finally see you, I have at best 10 to 15 minutes - and, for most of that time, I've got to fill in computer databases with information you've already answered two or three times."

"Code Black" mirrors the reality that many doctors face on a daily basis. Check out the trailer below and catch the next episode on Wednesday, 10 p.m. ET on CBS.