Occasionally the fire fighters will wait to hear from the alarm system who is needed for the emergency. However, in many instances, they'll move out before the alarm has even called out who is needed.
Stella Kidd is said to be from Milwaukee, WI. While an accent is heard, it seems to jump from Wisconsin to New Jersey to Brooklyn to dropped altogether.
In Season 8, episode 20 Brett and Foster respond to an incident at a pottery studio, where a woman has accidentally glued her lips together. A nasal cannula type device up her left nostril to help her breathe. They unglue her lips but still take her to Chicago Med. When she stands up, the cannula is still inserted up her nose. However, five seconds later it is gone, but neither Sylvie nor Emily have removed it.
Firefighter trucks always back in when arriving to the fire hall. This allows a faster pull out when required.
This is not the case when trucks arrive in 'Chicago Fire'.
Most departments, Chicago FD included, do not allow firefighters on duty to grow out facial hair on the cheeks or on the lower lip or chin as Lt. Severide often does. It interferes with achieving a tight seal on the SCBA (air) mask as the seal gasket on the rests against those parts of the face. Firefighters with too much facial hair will also fail the mask fit test for the same reason.
Mustaches (as often seen on Chief Boden, Mouch, Otis and some others) are not technically an issue, but some departments may have internal regulations that restrict them.