Linda appeared to be welcoming to Sarah on her first day at the office, but she quickly showed her true colors and saw Sarah as a threat--accusing her if being an obstacle in Linda's quest to replace their boss, Dr. Abbott. She continued antagonizing Sarah in response to Sarah's protests to Linda's controversial procedures, which included (but weren't limited to) instilling implants in a ten-year-old pageant contestant. After Linda defended her practices, both women were called into Dr. Abbott's office.
While this was going on, Kilee Yeager (Sarah's younger daughter and the main protagonist) was upset over Linda's treatment of her mother and used a demonic voodoo doll that she had found to make Linda see how good dentist she is. Similar to the previous times that Kilee put the doll to use, her wish was granted, and Linda started praising Sarah, who was bewildered by her change of attitude.
Heel TurnHowever, later in the film, Linda arrived at the office disheveled and acting belligerent towards Sarah, who she later accused of sabotaging her. She went on a maniacal rant and accused Sarah and Dr. Abbott of plotting against her, while threatening to harm not only Sarah, but Chrissy and Kilee as well, after which she spat at Sarah and left in a psychotic rage.
In the film's climax, Linda turned heel by attacking Sarah with a taser, doing so after attacking and tying up the office's receptionist, Allison. After the attack, the evil Linda tied up Sarah to a chair, laughing maniacally as she made a deranged attempt to prove her worth by operating on her. During this, the villainess revealed that her father stated to her that she would make a better eye doctor, leading to Linda taking the drill and attempting to jam it into Sarah's right eye.
Sarah later escaped and fought against the villainous madwoman, who stated that she would kill Kilee for putting her in the dirt, revealing that Linda's heel turn was due to being possessed by the doll's evil spirit. The scuffle ended with Sarah subduing Linda with her own taser, and it can be assumed that Linda was arrested for attempting to kill Sarah.
- "You have ruined everything! You have taken everything from me, and now I'm going to take everything from you! Especially that little brat Kilee; that one has no respect, burying me in the dirt! I'm gonna make sure you hear her cries of mercy!" (Dr. Linda Ryder's maniacal rant during her attempt to kill Sarah Yeager)