What to do when filming, for example, there is a picture from the first angle in the elevator, but a third angle can be released, and no one is filming.

There are many ways to do this, such as hiding the camera through a blind corner, or the actual camera is too small to be found. The simplest thing is to shoot multiple videos from different angles at a time, and then collage multiple videos together through editing of later video software, so that a video can have multiple angles. You won't see people and machines shooting, and there are many ways. If you are interested, you can go deep into school.