Chapter Seven marks the beginning of the second day on the Shutter Island, and the worsening weather means the marshals are stuck on the island despite their plans to leave. Teddy decides to explain Rachel’s code to Chuck and Cawley: Teddy has discovered that by adding the numbers in different permutations, each totals the number thirteen. Cawley explains that thirteen is “‘a significant number to schizophrenics,’” and given Rachel’s paranoid delusions, Cawley is not surprised that she fixates on that number (99).

Furthermore, Teddy explains that the numbers “47” and “80” are actually Rachel’s name in code. When he equated each letter of Rachel’s name to its corresponding numerical order in the alphabet, adding those figures together resulted in “47” for Rachel and “80” for Solando. The only number Teddy has not cracked is “67,” and neither Cawley nor Chuck can offer any insight. Teddy cannot shake how Dolores told him to “check the beds” in his dream, but neither he nor Chuck know how many patients are on the island (104).

Although Cawley appears impressed with Teddy’s logic, Teddy cannot shake the feeling that the doctor had already cracked the code. But Teddy cannot think about this new puzzle for long because he has to conduct patient interviews with Rachel’s fellow group therapy participants.