It's good manners to obey your superiors and make them feel good! And so, they start asking for drinks and snacks. Iida so naively wants to please them. Bakugo tries to warn him ab how they are taking advantage of him!

They discover the director and his assistants in the room. They are told the guys they were dealing with were villains and Kaminari quickly sends Iida a message. The villains admonish Iida, saying he shouldn't take out his phone in front of ppl. Put it in "Manner mode".

They lie telling him they're going to meet an important senior. Iida notices the luggage is heavy. The next moment, he assumes he's carrying souvenirs they'll give to this acquaintance of theirs haha.

He starts questioning if it's polite to pass through places like this (sewers) They bullshit it's because you're showing your acquaintance the utmost respect by lowering yourself before the meeting them. (like, they are underground pfft)

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)