Jane Margolis' death was originally planned to be so much worse on Breaking Bad. The character, played by Krysten Ritter, was introduced in the middle of the second season but she met her fate just a few episodes later. Despite her short time on the series, Jane made a lasting impression, especially in the eyes of her boyfriend, Jesse Pinkman (Aaron Paul).
When Jane made her Breaking Bad debut, she was a tattoo artist who also served as Jesse's landlord. Initially, she wasn't Jesse's biggest fan but they eventually became a couple. Jesse's influence broke her effort at recovering from her drug addiction. A bit too much about Walter White (Bryan Cranston) and Jesse's criminal endeavors was shared with Jane, which became a major issue. Jane blackmailed Walt but he still hoped to reconcile with Jesse so he arrived at his apartment. Jesse was passed out and Walt tried to wake him as Jane began choking on her own vomit due to an overdose. Walt remembered her threats and stood aside while she asphyxiated to death.
Jane's demise was one of the most brutal deaths within Breaking Bad. This was a major feat considering the multitude of memorable deaths in the series. The death was almost even more bleak in the earlier versions of the script. Series creator Vince Gilligan has shared that the original scene featured Walt injecting Jane with more heroin while she was unconscious, directly murdering her. Another version saw Walt purposely turning her over on her back so that she choked. Instead, Gilligan filmed the scene to show that Walt accidentally caused her to turn her on her back as he was trying to wake up Jesse.
The earlier versions of Jane's death were much darker and they were met with negative reactions by the network. Walt lost his sense of humanity down the line but the writers thought it was too early for him to directly kill someone who was only a minor figure in his way. When Jane was suffocating, Walt rushed to the bed as if his reaction was to save her. This was to prove that there was still a sense of good in him but he was racing down a dark path.
Despite toning down the scene, it still had an effect on Walt, as well as actor Bryan Cranston. The actor has been vocal that Jane's death haunted him as he envisioned his own daughter in that bed while filming the scene. That raw emotion was transported into Walt through Cranston's performance considering the character's reaction following the tragic event. Jane's death then caused Jesse to enter a downward spiral to a very dark place. It also started off a chain of events leading to a devastating plane crash which was chronicled by the mysterious pink teddy bear.
Jane appeared in a flashback during Breaking Bad season 3, when Jesse was looking back on their relationship. Walt also carried the guilt left by Jane's death. That guilt was symbolized by the season 3 episode, "Fly." The truth about her death was used when Walt spitefully tried to hurt Jesse at the end of the series. Ritter reprised her role for a cameo in El Camino: A Breaking Bad Movie. She appeared in another flashback detailing a conversation she once had that turned into words to live by for Jesse and his future.