It certainly did not appear that one could easily get past the apartment building's front door without a key.

This is what two years without a key will do to a man.

He led the two men to a small door; it opened without a key.

For years we have had problems with the ancient front door to our building, which is easy to open without a key.

Even the lifts would not go there without a special key.

"No one can get in the building at night without a key."

Once it's closed, no one can return without a key.

No one could get into her house at night without a key, she had said.

There would be no opening this door without a key.

And how do you get into a locked room without a key?