So, a few years back, there was a video online demonstrating an "Under the door lever lock tool" and here is a video that demo's how it works:

On imgur, someone demo's the use of an smartphone with video using one of the cameras under the door, to help see what is going on with the grasping of the door handle:

This is probably a well-known enhancement to the above tool, but was new to me; clever.

I thought I would point this out for others that did not think of joining these two pieces of technology, or have not seen it.