Beat it - Tradução em português

TO BEAT has many meanings, not just "Go! Leave!"

When your team plays against another team and wins, you beat the other team.
Inter beat Gremios 7 to 3.

If your rug is dirty, you put it over a line and you beat it to get the dust out.
I hate to beat rugs. The dust makes me sneeze.

When you make an omelet, you must beat the eggs.
I was beating eggs for a Denver omelet when I dropped an egg onto the floor and it broke. What a mess!

If someone tries to rob your brother, perhaps he beats up the robber.
The pickpocket was beaten badly by the crowd at the bus station.

If you cannot understand something or don't know something, you can say "It beats me."
It beats me why he does that. I just don't understand him at all.

You mention "Cair fora", what does "cair" (to fall) have to do with leaving/going? Languages are seldom (never?) logical. We must understand how an expression is used and then use it until it becomes a natural response. Right?

Complemento:

Ouvindo a música Beat It do Michale Jackson, me surgiu uma duvida, porque o beat it significa "cair fora" sabendo que beat significa : bater/batida, etc. =)

Trata-se de uma expressão.

As expressões não seguem um padrão definido para se formarem. Devemos entendê-las dentro de um contexto, de forma ampla. As explicações para sua formação? Quase sempre não há uma. Devemos aceitar e aprender a usar.