Although the lights in the room were turned on for a very brief moment, it did not escape Peter's notice. Under what circumstances would a person turn on the lights and then quickly turn them off? This was not difficult to explain. The person was doing something unspeakable, afraid of being noticed by the people outside. However, they also needed a light source. Perhaps a fleeting light was enough to do many things.
Why did Peter know about this method? It was because when he was young, his father used this method to save electricity. Thus, the points their family used on the lights each month were the lowest in the nearby neighborhood.
As for Anna, she must have used this method in her dormitory not to save electricity, but for another reason.
More than an hour later, light appeared in Anna's room again. As usual, it was turned on before quickly being turned off.
