I can only say what I can based on the limited knowledge I glean from news reports, but if this wasn't deliberate (and right now I don't have an opinion one way or another), it points to some kind of really basic & previously unknown engineering or manufacturing flaw that could not be detected by normal inspection techniques.
At this point, it's too soon to give up ALL hope for anyone in a vehicle that went down, but it's not looking good.
Oh, and just to put some perspective on this - there's almost nothing you can do to be "equipped" for something like this, with, perhaps, the exception of having a window punch and a seatbelt cutter nearby, and those are only good if you a)can get to them and b)know how to use them correctly.

Otherwise, this is one of those times where physical fitness can mean literally life or death, because if you're fat and out of shape, you won't have the strength you might need to survive the fall, get out, and swim. Forget helping someone else if you can't help yourself.

I was reminded of this fact the other night as we did a water rescue drill, in which I was in the Delaware River, fully clothed, with shoes on, and wearing a PFD while strapping a "victim" (another firefighter) to a backboard and lifting them to a rescue boat 8 times while we were in 14' deep water. It was exhausting and I had a PFD on. Without a PFD I probably would have been able to swim to shore and that's about it.

Ultimately, it's not gear that saves your ass, it's your well-maintained body & brain that does.