The villains are in a hurry and knock down a civilian, Iida offers to help him but the thieves tell him to forget about it. They don't give a damn about a person falling, manners are more important (and they wanted to be punctual in their escape)

Iida yells that he believes discipline and manners were originally meant for the sake of others. He'll only follow etiquette if it gives priority to those in need! [that's why he helped them]

Their act is up, they gotta run. All Iida has been learning was a hoax! "Ingenium won't allow you to use manners for evil!"

The villains thought he'd obey anything they say as long as it was ab good behavior. Bakugo and Kaminari tell him their class prez wouldn't go that far. At last, they can start the course they came here for. The director is amazed by Bakugo... bc he needs to be corrected. 😞

Every time these kids mention Bakugo and Todoroki everything goes downhill but they win in the end. I trust these kids more than any theory out there.