The President of the Bank, André Vernet, quickly gets himself preened and prepped for battle at the bank. He often had to protect gold key clients from law enforcement, but in this situation he just wants them out of the bank before there is trouble.
But when he gets into the vault, he's stunned into silence. He knows Sophie…but doesn't tell her that.
Whoops. When she tells him her grandfather was murdered, he gives away the fact that he knew Jacques Saunière. They'd been dear friends. He also knows that these two people are wanted for his murder.
He wishes he could help them figure out the ten-digit code needed along with the key to gain access to their box, but he has no clue what it could be.
When Sophie presses him about the Priory of Sion, he starts to sweat.
Vernet is notified the police are already there. He tells Langdon and Sophie that he will do whatever is in his power to get them out of the bank undetected, but after that his hands are tied.
He dashes off to make arrangements.
Langdon, meanwhile, is grinning, 'cause he knows the account number. He's pretty sure it's the number Sauniére wrote next to his body that has been puzzling the cryptologists ever since.