Anyone have any idea of the specific mechanics they use to withdraw from the vault? Do several executives meet in a special room at a certain hour, with their k

Anyone have any idea of the specific mechanics they use to withdraw from the vault? Do several executives meet in a special room at a certain hour, with their keys on paper/usb, and type them into an air-gapped machine one-by-one? I wonder how they handle a lost key, do they have to move $1 billion+ of Bitcoin to a new wallet each time?