in a hotel room at 2 a.m. someone violently knocks at the door. It could just be someone drunk who knocked on the wrong door, but it could be something worse. Do you look through the peephole to see who it is? It could be someone with a long sharp object ready to shove through the lens into your eye? Or it could be someone with a gun fitted with a silencer ready to pull the trigger as soon as they see a slight change in the light. Do you even want to know?