Fans have been asking the same question since The Pitt Season 2 premiered on Thursday: "Where is Dr. Heather Collins?" For the uninitiated, Dr. Collins, played by British actress Tracy Ifeachor, had a romantic relationship with Dr. Robby Robinavitch. Therefore, the fourth-year resident doctor was one of the most important characters with a link to Robby's personal life.But Heather Collins is nowhere in the season 2 premiere that was released this week. The answer to this question lies in learning what happened behind the scenes of the HBO series.Tracy Ifeachor had exited The Pitt Season 2 last year: View this post on Instagram Instagram PostIt seems that Tracy Ifeachor's exit from the HBO series was amicable. While we don't know why she exited the series, Ifeachor continued to promote the first season during the awards campaign. She announced her exit from the series last July through an Instagram post with the following caption:"What a blessing to be a part of this first and foundational season of #ThePitt on @hbomax . It was an absolute privilege to play Dr. Heather Collins in such a groundbreaking season and piece. Thank you to everyone who has watched & supported Season 1 & shared their stories with me. #TCA Awards #FYC #allthethings 😘 @thepittfanpage @warnerbrostv @manoloblahnik @olgatimofejeva @guylaj_styles @carolagmakeup @vraiofficial @vision.pr @jeffreychassen"Even producer John Wells addressed Ifeachor's exit from The Pitt Season 2 in The Hollywood Reporter interview a month after her exit:"Look, the show is set at a teaching hospital. And if you’re a fourth-year resident in a teaching hospital, your time there is done at the end of that year. Not to scare any of the other castmembers, but people don’t stay at these hospitals forever. They’re going to roll off, and that will be part of the evolution of the show. We’re not committed to doing a year every season as we go on, but we can’t say that we’re going to be true to the medicine and teaching hospitals and maintain the same cast for the entire time."It seems that the writers of The Pitt Season 2 seem to agree with Wells's take and seem to have written Dr. Heather Collins out of the series. Noah Wyle was interviewed by PEOPLE after The Pitt Season 2 premiere:"She's the one that got away in some ways. He could not have given her what she wanted. She was a rockstar on an ascension that he would only have been an impediment towards. And if she's found happiness, God bless."Wyle further described Dr. Robby like this in the same PEOPLE interview:"He is a pretty lonely guy outside [of the hospital]. That's what we build towards the end of the season. This is the only place he's a fully realized individual, but this is the last place he's able to exist in right now."What is The Pitt about?Both the first and the second seasons of the acclaimed medical drama revolve around a group of healthcare professionals in a Pittsburgh emergency room. Consisting of fifteen episodes, each season covers the 15-hour shift."THE PITT is a realistic examination of the challenges facing healthcare workers in today’s America as seen through the lens of the frontline heroes working in a modern-day hospital in Pittsburgh."The Pitt Season 2 premiere and the entire first season are available via streaming on HBO Max.