3rd clue: just happened to have his camera running and pointed in the exact location where the saucer appeared.........
You don’t know that it is a ‘saucer’, and the ‘camera’ may have been pointed in that direction to record the building and the operator noticed the object in the sky. The object could have been a Russia aircraft flying straight toward the camera albeit far away and made a sharp right turn which looked to the camera/observer like the object was stationary then darts to the observer’s left.