A person who is in a room may decide to move into another room. Into suggests movement.
Examples:
After waiting in the hallway for 20 minutes, I finally walked into the manager's office.
Practice:
(a) Doctor Who stepped _____ the Tardis, and ______ a moment he was gone.
(b) The chief value of money lies ______ the fact that one lives ______ a world ______ which it is overestimated.
