Dr. Ethan Choi (Brian Tee) seeks answers on a stabbing incident at his apartment complex on the upcoming episode of "Chicago Med" season 3.

Titled "Folie à Deux," next week's episode will see Ethan's neighbor get stabbed at their apartment complex. Determined to figure out why the incident happened, he seeks help from April Sexton (Yaya DaCosta). Dr. Natalie Manning (Torrey DeVitto) must race the clock to save a baby with whooping cough, while Dr. Ava Bekker (Norma Kuhling) and Dr. Connor Rhodes' (Colin Donnell) are put to the test when the new physician Dr. Noah Sexton (guest star Roland Buck III) misdiagnoses a patient.

Elsewhere, Dr. Daniel Charles (Oliver Platt) finds himself in an awkward position when Dr. Sarah Reese's (Rachel DiPillo) estranged father (guest star Michel Gill) becomes his patient. He later realizes that Sarah has no idea that her father is seeking medical attention in the same hospital she works in.

A sneak peek shows Natalie speaking to the worried parents of her infant patient. She discovers that the baby never had any vaccines, which made his condition worse. Natalie and the other doctors must move fast in order to save the baby before it's too late.

Cartermatt points out that episode 11 will mark the start of more complications for Sarah. Viewers have already seen a lot of her worst fears, but it looks like the next episode will show a different side of her. Her estranged father will enter the fray and his arrival will be a surprise to Sarah.

Best known for his roles on "Ray Donovan" and "House of Cards," Gill is slated to appear in multiple episodes this season. It remains to be seen how Sarah will react when she sees him in the hospital.

"Chicago Med" season 3 airs every Tuesday night at 10 p.m. EST on NBC.