To put it mildly: a mass casualty incident due to a shipwreck Really complicated first day of Dr. Caitlin Lenox (Sarah Ramos) in Gaffney on Chicago Med Season 10. And to make matters worse, our current ER chief, Dr. Dean Archer (Steven Weber), didn’t get the memo about Lenox’s arrival, making things, well, tense.

Background: Lenox was hired after a neighboring hospital closed. With Gaffney to take over the backlog of patients, Sharon Goodwin (Epatha Merkerson) assigned Lenox to run the emergency room alongside Archer. Lenox was immediately in action on her first day, but her eagerness got on someone’s nerves – Archer.

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Read all about Chicago Med’s newest recruit, Dr. Lenox.

Dr. Caitlin Lenox did not receive a particularly warm welcome in Gaffney

Lenox wasted no time introducing herself when she arrived in Gaffney amid the mass casualties. “I came as soon as I heard the news,” Lenox said, shaking everyone’s hand. “Caitlin Lenox, the new director of the emergency department.”

Archer shook her hand hesitantly, completely confused by the interruption, and said, “Dean Archer, current Head of the emergency room.”

“Hi,” Lenox smiled. Having neglected to warn Archer due to the chaotic day, Goodwin hastily explained Lenox’s presence.

“I hired Dr. Lenox to run the emergency room with you,” Goodwin said to a confused Archer, quickly adding, “As equals.”

“Well, I need to brush up on my barista skills,” Archer joked.

“I was supposed to start next week, but I thought you might need help today,” Lenox explained.

“And apparently every day after that,” Archer noted.

“Look, I didn’t mean for you to hear it this way, and I sincerely apologize for that,” Goodwin said. “But Dr. Lenox comes highly recommended.”

“Of course,” said Archer, turning to his new partner. “How old are you?”

“How old are You?” Lenox asked without hesitation.

“Nice to meet you, Dr. Lenox,” Archer said with a shrug as she walked away to help a patient. Viewers may have been weary of Lenox’s skills after that exchange, but after Lenox jumped into action and snapped a patient’s dislocated knee back into place in seconds, her colleagues summed it up perfectly when they called her “tough as nails.”

Dr. Cailin Lenox and Dr. Dean Archer are two opposite sides of the same coin

The surge in patients following the shipwreck gave Lenox an instant understanding of Gaffney’s emergency room and its operations, and she quickly made changes. When Maggie Lockwood (Marlyne Barrett) pointed out that there were no hospital beds available for a second wave of patients, Archer directed the incoming patients to a nearby hospital. Overhearing this instruction, Lenox questioned Archer about his decision. Archer explained that they had reached a tipping point and could no longer provide adequate care, a term from his time in the military. Lenox suggested that instead of moving patients, they could convert the “wasted space” conference room into another hospital room.

“Your first day here and you know everything, right?” Archer said.

“Diversion of patients could cost victims of red-tagged patients valuable time that they cannot afford to lose,” Lenox said. “It also does not reflect an appropriate level of care.”

“They’re in the military,” Archer guessed.

“Army,” Lenox replied.

“I think that counts,” Archer said, shrugging.

“You?” asked Lenox.

“Marine,” Archer said proudly.

“OK, this is fun,” Maggie interrupted. “But I need a decision.”

Archer glared at Lenox before snapping, “Yes, that’s what she said.”

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The tug-of-war between Archer and Lenox was far from over, as she continued to work through patient after patient. When one of the residents, struggling to cope with the horrific scene, abandoned his patient in the throes of a panic attack, Lenox was stunned by the resident and Gaffney’s lack of preparation for the incident. Lenox fired the resident, earning her an angry visit from Archer, who had not been informed of the termination in advance. Lenox explained that Goodwin signed the termination and quickly reminded Archer of the “chain of command.”

“Are you worried that I’m here because Goodwin has lost faith in your ability to lead alone?” Lenox asked him.

“What concerns me is your impact on morale and your hasty judgments without consulting me,” Archer explained. “I ran this emergency room well before you came here.”

“Dr. Archer, your department nearly fell apart today,” Lenox told him honestly. “No plan for overcrowding, abuse of space, blood shortages, and a doctor who walked out and nearly took a patient’s life. I wouldn’t call any of that OK.”

“We were in the middle of a high-casualty incident,” Archer shouted.

“And in a few days, Jackson Monroe will close and nearly twice as many patients will come through those doors,” Lenox reminded him. “Today could be any day. I’m here for a reason, and it’s not to maintain the status quo.”

Watch Season 10 of Chicago Med Wednesdays at 8/7c on NBC or stream episodes the next day on Peacock.