It or any vehicle? For what it's worth, I wouldn't want to be in a Bradley or a 113 or a Hummer in a similar situation. I don't know of too many vehicles that do well when faced with a road collapse and falling into a body of water.
The roof hatches of a Stryker- or other vehicle- aren't of much use upside down. Neither the ramp of a Stryker nor M113 would drop if upsidedown, even if the operating cable was cut, since it's gravity that lowers the half-ton armored ramp. But at least in a M113, there's a door built into the ramp that can be manually opened to get out through the back.
The problem for the crew inside the Stryker that went in the water was that its hatches were padlocked shut, and rescuers had to get boltcutters to open them to get the bodies out.
-archy-/- <imgsrc