In the Depository Bank of Zurich, Sophie and Langdon use the key to get through the elaborate security measures—gates, metal doors, and so on. They arrive at the front office, where a guard greets them and points them to an elevator, which will take them to their vault. The guard recognizes the pair from the news and calls Interpol and the bank’s president, Monsieur Vernet. Sophie and Langdon make it to the vault only to find that they need an account number to access the box. They don’t realize that they have been discovered—or that they are locked in the vault. Fache sends Collet to the bank to apprehend Langdon and Sophie.
André Vernet, the bank’s president, hurries to the bank after hearing that the police are after high profile clients. Part of Vernet’s job is to keep the bank’s name out of the press, and he hopes to diffuse the situation. When he enters the vault, he can’t hide his surprise at seeing Sophie. He tells her that he was a good friend of her grandfather’s. She shocks him with the news that her grandfather has been killed.
Sophie begs Vernet for the account number, but he refuses, saying that only the clients know their own account numbers. He promises to smuggle them past the police, but Sophie and Langdon do not want to leave until they have opened the safe deposit box. While Vernet goes up to the lobby to try turn the police away, Sophie and Langdon remain in the vault and try to figure out the account number. Langdon realizes that the number must be the string of digits Vernet wrote on the floor before he died.
Langdon and Sophie have only one chance to enter the correct account number into the computer. Sophie looks over the numbers once more and decides that the account number must be the Fibonacci sequence. The number works, and the electronic system retrieves a safety deposit box from the basement for them. Inside is a small, heavy rosewood box with a rose inlaid on the top: the Priory’s symbol for the Holy Grail. Sophie and Langdon are surprised when they hear gurgling noises coming from inside the chest.
Though both Robert Langdon and Bishop Aringarosa are on a quest to find the Holy Grail, they are interested in it for different reasons. Brown dispenses hints that Langdon has had entanglements with the Church in the past, but Langdon’s motivation seems to be essentially academic. In contrast, Aringarosa wants to find the Grail in order to cover up the truth and secure Opus Dei’s power.
Silas’s devotion to Bishop Aringarosa is extreme. He views the Bishop as his savior and finds his life’s meaning in serving him and Opus Dei. His devotion is not only unhealthy, but dangerous. It returns him to the violent state of mind he was in before his conversion to Christianity. Silas’s moral quandary over the killing of Sister Sandrine initially seems to be a sign that he has repented and realized how wrong he was to kill indiscriminately. But then it becomes clear that Silas is less upset about Sister Sandrine’s death than about Bishop Aringarosa, whom he credits with his salvation. It seems that for Silas, anybody associated with Opus Dei is precious, and anybody outside of the fold is expendable.