A large panning light that would move from position to position faster than seemily possible.

A friend and I were discussing life issues at a local lake.  We were parked in my car talking when I kept seeing something flash/flicker out of the corner of my eye. I finally could not go on talking with her anymore and said "what is that?" as I turned my eyes up towards the sky. She had been noticing it too, but had yet to say anything. We both watched the light slowly pan around as if it was trying to find something similar to what one might see a helicopter do. There was no sound however and every so often it would move positions. It was very very quick when it did this....it took no longer than a snap of the finger to get what looked like many yards away from it's present position. We watched with curiosity, excitement and fear as it continued this for many minutes. I even went as far as flashing my car headlights out over the lake to perhaps get its attention, but never did. After a while it began to sink in to us what we were looking at and we decided to call it an evening. Fear drove us home as we left the object still panning its light down upon the ground....still speedily moving from one position to another…