In the beginning of Hunter Killer, you are in a flooded tunnel. Already it is a grim sight, but things get even worse when you think about it. This isn't an everyday tunnel. It's actually the Brooklyn-Battery Tunnel, the longest continuous underwater tunnel in North America. And what type of highway is carried by the tunnel? An Interstate Freeway. As a road nut, I know of the main design advantages of Interstate Freeways: They're fast, they have heavy access control (i.e. access is limited to ramps), their carriageways are separated physically, and they're designed to be busy. Typically, these four aspects of a freeway keep things running smoothly. But when a torrent of water starts to flood the tunnel, suddenly every strength of the Interstate turns into nails in your coffin.
Right off the bat, the fairly high speed limit of 40 MPH means you have a long stopping distance, and traffic business means you can't make a sudden forceful stop, nor can you switch to reverse and drive the wrong way. You can't try to cross to the other lanes, they're in a separate tube. And there are no nearby exit ramps to get to high ground. You can't jump out of your car and run, either; the tunnel is almost two miles long.
Traffic at the entrances to the tunnels isn't spared from disaster, either. The same problems above also greet the traffic there. You again have a long distance to stop, slamming on the brakes risks a crash, and it's not easy (though possible here) to cross to the other lane to escape. This time, lack of access control is not as harsh a problem since exits are near. Still, you're a sitting duck to carpet bombing. And the Russians could simply bomb going toward the tunnels to prevent escapes.
