And just to hammer the nail in further, one NPC asks you if you were on the train and says "you were the lucky one."
Dr. Sigmund's Orphanage of Fear. All the kids there are terrified and cannot wait to turn eighteen, because he won't let them be adopted and won't let them leave until they're legal adults. Why are they afraid? He tortures them with electricity in his "therapy" sessions.
Heather ends up there after her father dies, and he immediately marks her as his next "patient". As if she hasn't been through enough. Made even worse since Corey asks you to look after her, and you failed.
Talk to people in the Obsidia ward during the attack. One crying girl will be too afraid to go outside because the street collapsed beneath her boyfriend's feet while he was walking next to her.
Shade's gym. It's an old power plant with no power, so it's pitch black inside, except for the occasional flicker. The music there is a low, menacing tune similar to what you find in Lavender Town and doesn't change when you encounter wild pokemon. To get to Shade, you have to stumble your way through the darkness, lowering the doors with terminals, and every time you activate a terminal you see how someone died. One girl getting attacked by a Garchomp, another being decapitated, Corey committing suicide...and the less said about Shade himself, the better.
And then there's the fact that his Gengar is named after Corey, whose body he collected.
Those "visions"? Those don't show how someone died, they show how someone will die. The girl being killed by a Garchomp is Kiki, who is indeed decapitated by Solaris's Garchomp while trying to stop him from erupting the volcano.
The PULSE machines. Just three of those things were able to destroy half the city with just Tangrowth. Imagine what one could do with, say, a Gyarados or a Tyranitar. Or even better, imagine what a whole army of Pokemon hooked up to those things could do.
The prototype pulse machine forcibly evolved a Magneton into a Magnezone, which isn't all that horrifying except for the fact that in the pokedex, it is said to be impossible to do artificially. Its creator's on the other hand, went through the exact same process, becoming ZEL.
Using a move of the same type as the field usually strengthens in, with the game saying "the murk added to the attack" (or something). Use a Poison-type move in the Wasteland, and the game tells you "the waste joined in the attack". That place is alive, and it's not friendly.
Solaris. He's Dangerously Genre Savvy, cold, calculating, and has no qualms ordering his Pokémon to attack and kill defenseless humans. What Pokémon is it? A Garchomp—you know, the thing that Smogon banned to Ubers for being stupidly overpowered. And the game is not shy about showing how badly an ordinary human fares against it.
He orders Cal to throw Kiki's Medicham in lava. Imagine how traumatizing that would be for Kiki.