On Tuesday night's episode of "Chicago Fire," fans saw the emotional exit of cast member Charlie Barnett, who played the role of Mills.
Talking about Barnett's "dignified" exit, "Chicago Fire" showrunner Matt Olmstead said Mills was basically torn between choosing one family over the other, TV Guide reported.
"You're picking between two families in a way: Your family at the firehouse and your real family. He opted to now be with, and succeed with, his real family."
Mills received the clearance to return to the squad on Tuesday night's episode. However, instead of returning to Firehouse 51, he decided to leave the squad to open a restaurant in North Carolina with his mom and sister.
In an interview with The Hollywood Reporter, Olmstead explained why he decided to leave Mills (Barnett) out of the series' upcoming episodes.
"It wasn't specific to Mills' character or Charlie the actor. It was a general sense of looking at the show and what kind of new stories we could bring in, new blood we could bring in, which we do somewhat vigilantly throughout each season," he said.
Olmstead also explained how come Barnett's character was not killed off - literally.
"There was a big discussion about how he would leave, but we would never entertain the idea of killing the character off. We always knew from the beginning - once this idea started to get some traction - that we wanted a dignified departure for the character because that obviously leaves the door open down the road."
"Chicago Fire" airs Tuesdays at 10 p.m. on NBC.