So the nurse knew that the reflection is there all the time, and just wanted to make the mom feel better? That is I am assuming that the lights in the hallway are always on and the monitor is always on, etc.....
We cannot possibly know what the nurse knew, or what is ‘always’ there, but the basic nature of the reflections is pretty obvious. The only question is whether the source is sunlight, or artificial.
“Angels of light” are always Satan’s lies.