The "Grey's Anatomy" Season 12 premiere last week titled "Sledgehammer" saw the Grey Sloan Memorial Hospital doctors spring into action to treat two young girls who were hit by a train while making good on a suicide pact.

Meredith Grey (Ellen Pompeo) adjusted to her new living situation with roommates. She and Amelia Shepherd (Caterina Scorsone) fought over little things. Shepherd took a sledgehammer to the wall the two had discussed removing, and they've been fighting about it since.

Miranda Bailey (Chandra Wilson) fought for the Chief of Surgery position.

Jackson Avery (Jesse Williams) prepared himself for April Kepner's (Sarah Drew) return.

In "Grey's Anatomy" Season 12 Episode 2, "Walking Tall," that airs on Thursday, "The Nazi" -- otherwise known as Bailey -- starts her career as the new chief. The power goes to her head.

Bailey strikes fear into everyone, including Callie Torres (Sara Ramirez), who desperately wants Owen Hunt (Kevin McKidd) to step back into his previous role as chief.

SpoilerTV has published the episode's synopsis, which reads, "The pressure is on as a determined Bailey tackles her first day as Chief; meanwhile, April's marriage is in jeopardy and she finds herself unable to address her problems; Meredith struggles to juggle all her responsibilities and Amelia works to define her relationship with Owen."

ABC also posted a sneak peek of Episode 2 that shows Kepner with a mysterious rash on her back upon returning from the Middle East. The rash lands her in the isolation unit. She assures her fellow doctors they're overreacting, but Bailey won't allow her to leave quarantine.

"I should be chief," the lab coat-wearing Bailey says in the "Walking Tall" trailer. "Oh, wait. I already am!" She howls with laughter.

In the next scene, Torres brings Maggie Pierce (Kelly McCreary) up to date on the doctor who used to act like a tyrant during their hospital internships.

"You know what they used to call her?" Callie says of Bailey. "The Nazi."

Avery makes an ill-fated attempt to argue with the new chief in the video slip.

"You're impossible," he says, unaware of the wrath he's brought upon himself.

"Oh, I know you didn't say impossible," Bailey barks at him.

Watch "Grey's Anatomy" Season 12, Episode 2 "Walking Tall," which airs Thursday, Oct. 1, at 8 p.m. ET on ABC.