break in
(stress on "in") To break from outside.
The firemen broke in the door of the burning house.
To enter by force or unlawfully.
Thieves broke in while the family was away.
To enter suddenly or interrupt.
A stranger broke in on the meeting without knocking.
The secretary broke in to say that a telegram had arrived.
While Carrie and I were talking Bill broke in to tell me about a telephone call.
To make a start in a line of work or with a company or association; begin a new job.
He broke in as a baseball player with a minor league.
To teach the skills of a new job or activity to.
An assistant foreman broke in the new man as a machine operator.
To lessen the stiffness or newness of by use.
It is best to break a new car in by driving it slowly for the first few hundred miles.
He broke in a new pair of shoes.
Breaking in a new car requires careful driving at moderate speeds.
break into
To force an entrance into; make a rough or unlawful entrance into.
Thieves broke into the store at night.
To succeed in beginning (a career, business, or a social life)
He broke into television as an actor.
To interrupt.
He broke into the discussion with a shout of warning.
To begin suddenly.
He broke into a sweat.
She broke into tears.
The dog heard his master's whistle and broke into a run.