Crossover
The series exists in the same television setting as ER and Medical Investigation. Molly Price, Jason Wiles, Kim Raver and Amy Carlson appeared in a two-part crossover episode of ER entitled Brothers and Sisters (season 8, episode 19), while Sherry Stringfield appeared in the corresponding episode of Third Watch entitled Unleashed (season 3, episode 20). However, ER was mentioned as a pop culture reference during season two episode "Jimmy's Mountain."
A special two-part crossover event aired on February 18, 2005, establishing the television-universe connection by featuring the Third Watch and Medical Investigation teams working together.
Read more about this topic: Third Watch