Spoilers ahead for the March 22 episode of FBI on CBS, called “Scar Tissue.”FBI put the team on the trail of a serial killer after a local murder case took a turn, and the investigation took them to a hotel that resulted in a family connection for Alana De La Garza’s Isobel. Her father was in charge of the hotel, but wasn’t cooperating with the case – which turned very violent for the team – until his hand was forced. Isobel was convinced that Robert (played by guest star Nestor Serrano) was being difficult to punish her for not making time for him, and the tension came to a head at the end of “Scar Tissue” with the reveal of why she joined the FBI in the first place. Isobel didn’t actually endure any of the violence in this episode, as Tiff was caught unawares by the killer and attacked (although she survived) and OA (who has had a difficult enough season already) later had to fight for his life, and he almost certainly would have been killed if not for the timely arrival of Maggie to shoot the bad guy dead. It was a high-stakes and stressful hour for Isobel as her dad stonewalled the investigation, so when he showed up in her office unexpectedly, she didn’t pull her punches even when he tried to say that he was proud of her. Robert established that Isobel’s mom dreamed of working with the FBI, and after he wouldn’t drop the subject, Isobel explained her true reason for joining the Bureau: