General   (General discussion, talk about anything.)

the back door was an emergency exit, NOT an entrance, then he couldn't remember how many staff were on and how many were in the pub.

The back door serves the purpose of being both entrance and exit.
There is an area out side of the back door which serves as a beer garden, with both tables and benches for the use of the patrons of the pub.
People enter and leave by this door, so it is an entrance. Also serves as a smoking area.