Defintoolly wouldnt do the coloured water thing that is asking for trouble.
You said that your car was sitting on a slope, what end was the highest ?
If the nose was highest looks like it could be the window
If the tail is highest there is chance it could be the ariel mount !
As said though my money is on the window, as the water has a fair distance to travel if it was the ariel, but best to rule that out first to avoid windscreen expense