The film became harder to watch after Hurricane Sandy hit New York and caused tons of damage along with rampant flooding in many places, including the Hudson Tunnel.
The fact that a film with civilians and a first responder in New York City getting crushed or buried alive by collapsing rubble closes with a shot of the World Trade Center is fairly uncomfortable, too.
The surviors stumbling about the tunnel after the initial explosion dies down, confused, scared, and begging for help can be difficult to watch as well.
In 1999, just three years after the movie came out, the Mont Blanc disaster happened in an eerily similar way to the movie.
The explosion ripping through the tunnel. Countless helpless motorists can only swerve to the side or slam on the brakes before their car is consumed by a roaring wall of fire, several cars are flung back through the tunnel like toys with one car's gas tank exploding before ginormous fireballs explode out of both ends of the tunnel which then collapse, several motorists mere inches from the entrances and exits.
The aftermath of the explosion itself is a hellscape of burnt out cars, the sight of several cars who's windows broke under the pressure which caused the occupants to be incinerated alive, confused and injured people stumbling about, shouting for help.
Once the survivors swim through the flooded passageway, Elanor is quick to notice that Cooper, the dog who once belonged to her and Roger's deceased son, isn't in the room with them. Roger holds up the dog's empty collar and solemnly says that he couldn't hold him. Ellie tries to go back after Cooper but Roger stops her, saying it's too late and Cooper can't be brought back. Quite a few people in the room understandably tear up. Fortunately, the next scene reveals that Cooper actually survived, but not before what is described below.
Once the survivors begin to break down the wall of the abandoned sanctum, Kit looks back to see that Roger and Ellie aren't in much of a hurry to help out. Upon rushing over to the two, Roger looks over and says while fighting back tears, "I thought she was resting!". After Roger refuses to leave her side, Kit says that if Roger stays, he stays, not wanting a repeat of the Noodle Incident that ruined his career. Roger eventually decides to move on with the survivors but after losing his dog and his wife in the span of five minutes, one can't fault him for wanting to stay behind...
Woolseyism: In the Spanish version of the film, a person is heard saying "Shit!" during the explosion scene, as opposed to the original's "Jesus Christ!".