On Hollywood Hacking: Smartphones are basically tiny computers with networking now, and any command a computer was programmed to execute (Make light go green now, for example) can just as easily be executed by a hacker, remotely if the computer's networked. A lot of the stuff here isn't that farfetched.
As for scripting, it shouldn't be that hard to simulate realistic behavior with enough processing power. Give each NPC a couple stats (It looked like NPCs had randomized occupations and trivia, which could influence or hint at their stats). A basic one would only need two:
Tension - The danger the NPC believes itself to be in
Morale - How the NPC gauges its ability to survive or overcome the situation, ranging from "Guy in the car in the demo" helpless panic to "I got concealed carry, let's give these turr'ists what fer" impetuousness.
Add in a random element to determine how an individual NPC reacts, based on his stats, and you've got a bunch of NPCs behaving in a semi-realistic fashion, and since most people don't pay much attention to NPCs the simplicity of it probably won't show through a lot. You could probably add more sliders too to help determine just how the NPC will react.
EDIT: Did he ever switch characters? It was always the same guy, though right before he hacked the lights he pulled a mask over his face.
EDITEDIT: Is there any indication at all about anything regarding custom content? There's some hints that there might be multiplayer, but they never actually said anything about it.