Many characters have been cautiously approaching Dr. Lenox (Sarah Ramos) since she arrived at the ER at the beginning of Chicago Med Season 10. She is a tough personality who doesn't care whose feelings are hurt if it means improving service delivery. She's used to people tiptoeing around her, so when Dr. Hayes (Brendan Hines) challenged her during this year's One Chicago crossover, Lennox was pleasantly surprised. One would have figured that either Dr. Hayes was very courageous or there was something odd about him. A sneak peek of Chicago Med Season 10, Episode 21, "Baby Mine..." hints at the latter when an allegation against Hayes is lodged. Meanwhile, Maggie (Marlyne Barret) and Frost (Darren Barnet) fight to get a pair of lungs for a young cystic fibrosis patient, Hannah (Jessy Schram) learns whether she can become a surrogate, and Ripley (Luke Mitchell) and Morris (Lee Jones) treat the daughter of a tech billionaire battling leukemia.