Look around the corner, and try not to scream It's me!
“Doors have eyes
walls have ears!
On technical aspect the story is conveyed by setting up new information in each scene leading to a final payoff moment.
The segments share the fact that this could be any of us and what is being seen is in fact us earlier today without the physical presence of the intruder hence sparking the idea of not being alone all that much!
The entire film was shot in and around the apartment of the lead actor in West Hollywood with not more than three takes for each scene.