I'm not sure what your point is?
They used the word "collision," but the caller didn't.
I am thinking, at that time of morning, in that kind of country, they could have swerved to miss a deer and ended up in the water.
There is a little gadget that you can keep on your key ring that breaks safety glass. Have you heard if they were still buckled in their seat belts, or did it appear that they tried to get out of the car?