All very well with the benefit of hindsight. Suddenly finding yourself in a sinking car...? 3-4 minutes goes pretty quick. Most people would probably waste 1 or 2 trying to figure out what was happening, getting over the shock, then trying to get the door open. Once you realise you can't get the door open, you go for the window, and guess what, they don't work. You panic. All over. Even worse, you waste time getting your phone out.
When I lived in the Territory, and crossing rivers was a relatively regular occurrence, I was always amazed how many people with with flash new electric everything 4WD's would charge in without a second thought. I always wound the windows down before a crossing.