'Westworld' Season 3: Episode 7 Reveals Caleb And William As Having The Same Patient Registration Number

SPOILER ALERT: This article discusses Episode 7 (titled "Passed Pawn") of HBO's Westworld Season 3. Please proceed with caution if you have not yet viewed all available episodes and wish to avoid spoilers.

As previously reported by The Inquisitr, the latest episode of Westworld was expected to go a long way to explaining Caleb's (Aaron Paul) backstory. Previously, many viewers suspected the character had more to his story than what had already been shown so far. Along with some extensive revelations, as Insider points out, some fans may have missed another major reveal.

Episode 7 finally explained that Caleb had been an inpatient at the same facility as William (Ed Harris), also known as the Man in Black. During his stay there, he had successfully had his memories altered into a new version of his perceived reality. With the introduction of a new artificial intelligence (AI) system called Solomon, Caleb's true identity was revealed, showing that he had been reprogrammed to destroy others like him -- those that Engerraund Serac (Vincent Cassel) referred to as "outliers" or "agitators."

Serac wants these outliers destroyed in order for his AI system, Rehoboam, to run smoothly. Hence why he had many of them taken in and reprogrammed such as Caleb was.

Previously in Westworld, William had also undergone reprogramming at the same institution as Caleb. It was revealed in the latest episode that both characters also shared something else in common.

Luke Hemsworth as Ashley Stubbs, Jeffrey Wright as Bernard Lowe, and Ed Harris as William, as seen in Episode 7 of HBO's 'Westworld' Season 3
HBO | John P. Johnson

As pointed out in screenshots by Insider, both Willam and Caleb share the same patient registration number. "U M27021001912B" is initially shown as William's registration number. However, after Bernard Lowe (Jeffrey Wright) and Ashley Stubbs (Luke Hemsworth) start digging around, they discover that this seemingly unique number also belongs to Caleb.

As yet, it is unclear what sort of significance this will have regarding the two characters. However, viewers are already positing that Caleb and William could be one and the same person. Although, on Twitter user also pointed out that the number might be slightly different, leading to speculation that the two characters are somehow linked but not the same person.

"One had a 1 where the others has an I so not the same but similar (why?!)," the person wrote.

There also appears to be some sort of potential error. In addition to the screen showing the matching numbers, it also gives Caleb a different number on the same screen. This appears to have a "47" within it, whereas the other shared number doesn't. It is possible this is an error by HBO regarding the use of the same numbers. However, as fans point out, nothing is ever an accident when it comes to this sort of thing in the hit sci-fi series.

Of course, viewers will just have to wait until the Season 3 finale on Sunday night in order to find out more.