It was hard to open it all the time, so people designed a small door for the personnel.

任何时候都很难打开它，所以人们设计了一个小门给全体人员使用。

youdao

At the end of the class, the lecturer would usually leave by a small door near the blackboards, while the class would leave through the large doors at the back of the hall.

通常讲完课，讲师都是从黑板边的一个小门离开，而同学门都是走教室后面的大门。

youdao

They would live in a small house with a green door and a new thatch.

他们会住在一座有一个绿门和新茅草屋顶的小房子里。

《柯林斯英汉双解大词典》

A book drop is the small metal door in the wall of the building where people can return books when the library is closed.

VOA: special.2009.02.23

The Marines attacked. They broke open a small hole in the door of the brick building.

VOA: special.2009.07.02

The small four-door car is about three meters long.

VOA: special.2009.03.28

She described the main exit as a "small door for lots of people to come out by".

BBC: Eyewitness: Kiss night club fire in Santa Maria, Brazil

Booth, once inside Ford's, wanted to cross behind the stage all the way to the other side of the building, where a small door led to a narrow passageway that ran west to Tenth Street and the front of the theatre.

NPR: Excerpt: 'Manhunt'

Police tape covered the front and the small back door.

NPR: Tests Link Deadly Ricin To Obama Letter Suspect