Quoting my own previous post in response to your question and attaching some diagrams I made up quick.
Some factors that come into play with how water would enter the vehicle:
- whether the Driver-Side Rear (D-R) window was rolled down before or after the vehicle entered the water
- when the Passenger-Side Front (P-F) window was broken before or after the vehicle entered the water
I think most of us are assuming the D-R window was already rolled down, but it is possible that, in scrambling to try to roll the nearest [Driver-Side Front] window down before sinking, someone could accidentally hit the button for the rear window instead.
As for when the P-F window broke, I see a few possibilities:
1. In an unrelated incident or collision before entering the water (I see this as unlikely, considering the lack of other damage to the vehicle)
2. Accidentally, in the process of entering the water (Maybe if it was impacted on that corner of the roof just right when it landed on the bottom?)
3. Intentionally by someone trying to escape after the vehicle entered the water
Either way, though, the nose of the vehicle is going to be pointed downward in the water due to the engine's weight, so water from either window will trickle downward toward the front of the vehicle as it enters. IF it was only entering from one side (through D-R), that imbalance may have contributed to the vehicle barrel-rolling onto its roof ("turtling") as it descended.
IMO, MOO