Coverage
Someone enters
A door opens and a new person changes the scene.
An entrance has three views: the door, the person already inside, and what the newcomer sees. Shoot all three and the edit can choose whose scene it is. The reaction shot of the person inside is usually the most important one.
Watch out. Shoot the door opening from both sides. You will want the reverse.
Establishing shot: the corridor or the outside.
Wide on the door. It opens, the newcomer enters.
Reaction of the person already inside.
POV from the doorway: the room as the newcomer sees it.
The newcomer steps in. Slight low angle.
Two-shot as they meet.