@Sesc It's been a very long time since I've been to the Tower of London but from what I remember you walk through a bunch of information rooms and the vault doors are just before the shiny treasure so probably at 5. Don't take my word for it though. Also there is a long line of crowns and assorted jewels with a moving conveyer belt like walkway in what is probably Treasury. Room 2. Oh yeah @Sesc. For a full run down watch the movie Johnny English. Especially if you are writing a break-in. The security of the crown jewels is extensively covered by MI5's finest agent.