I feel like I’ve seen, at least dozens of times, the movie scene where someone is shouting “Don’t panic! Stay calm!” as chaos unfolds around them, people run past, etc.
Usually the trope is that this person is an idiot and will, in a few frames, be killed, or (in a comedy) trampled.
But for some reason I can’t actually think of what movies I’ve seen this in. Any help?
ETA: I’m not looking for a specific movie, just some examples of that generic scene.
Animal House (of course…).
Airplane 2 (complete with commentary sign). It’s on YouTube, though I don’t have the url at the moment…
Hitchhiker’s Guide to the Galaxy should have a scene like this
Brian
I thought that the trope was that the first person to start panicking and screaming will be the first one killed (Speed had an example of this, I think).
Airplane! has a few scenes like that (paraphrasing):
“This is your stewardess speaking, everything will be all right, just a little turbulence…by the way, does anyone know how to fly a plane?” (panic ensues)
“We’ve lost two of our engines, we can’t land due to bad weather, and both the pilot and co-pilot are ill and unconscious.” (everyone remains calm)
“Is there anything you’re not telling us?”
“We’re also out of coffee.” (panic ensues).
In the movie, the description of the HHGTTG book itself has a large Don’t Panic sign on its back cover. I’ve used this video many times in my beginning computer classes.
Animal House is the first one I can think of (wasn’t it Kevin Bacon?). There’s a scene in one of the Naked Gun movies in which Frank is saying “nothing to see here” while all kinds of crazy stuff is going on behind him including a fireworks stand on fire.
ISTR The Fifth Element had a scene like that.
Once the bomb is detected on board the Fhlostan Paradise, the security officer (Mr “I’ve never negotiated before.” Hmph, have to go look that up, I have no clue what his name is. Dum dee do. His name is Fog. Now back to your regularly scheduled thread) is trying to control the passengers with calm reassuring words and instructions. He is of course trampled by the mad rush for the lifeboats.
As I said above, the latter is Airplane 2, and it’s better in context, of course. 
Leaper:
I didn’t realize, I thought it was in the first one. What I did remember was from Airplane 2 (and not in the first) was that there was a flashing sign behind the stewardess that said “Don’t Panic” and then changed to “OK, Panic.”
Not quite the same thing, but there’s the scene in Mars Attacks where a couple of aliens are running around, gunning down innocent people, while carrying a “translator” device saying things like, “Remain calm! We come in peace!”
Manos: The Hands of Fate
Hal says to his wife “don’t panic” while looking for Debbie who just wandered off. Of course Hal doesn’t meet his fate until the end of the movie, so it doesn’t quite fit the OP.
Thanks everyone, it’s amazing how many of these I forgotten.
In the play-within-a-film in Noises Off!, the character played by (well, really the character played by the character played by) John Ritter starts panicking over ghosts, and runs down the stairs yelling, “Don’t panic, don’t panic!” As each iteration of the play deteriorates more, the action surrounding him is more chaotic and he’s in more of a panic.
Watership Down. “What are you talking about? Dogs aren’t dangerous!!!” And the General was never seen again…
I immediately thought of the scene from Animal House.
From the Doctor Who episode The Girl Who Waited, the Doctor, Amy and Rory visit a quarantine facility. The attendant robots amble around, ready to help patients in need, but if somebody gets rowdy, they intone “Do not be alarmed. This is a kindness” and shoot the interloper with paralyzing darts.
The first Naked Gun has a scene where a man riding an explosive device and crashes into a fireworks factory. As the fireworks are erupting and the building catches fire, Leslie Nielsen stands with his back to the chaos. Oblivious to what’s transpiring behind him, he keeps shouting to a gathering crowd, “there’s nothing to see here…please disperse!”