Obviously it's for a reason. Why else would this be made into something of a show?

[ What he means is how everything is timed. With the district opening up. The sounds that had drawn them all in. Conspicuously finding a key... All of it just smells of whatever powers or persons are at play setting it all up. And Zelda is right. She's only saying what Bakugou has been thinking:

That they are being careful. Calculating.

He can't think that showing them all these things are actually a good thing. Bakugou can't see reason to reflect on items just out of the "goodness" of someone's "heart."

After a moment, he huffs. Her saying that there's much that people have left behind, or there's the potential anyway. Katsuki's eyes shift towards the box that supposedly has something in there for him. Part of him is half terrified of what it could be - there's a lot of things that he regrets. Another part of him is curious what these people would think to throw at him. ]

Fine, fine. I'll look. Meanwhile tell me if that tablet thing of yours is actually working or picking up any signal.