[Yeah, it's...Izuku would much rather Katsuki be yelling at him right now, if he's honest. That deathly calm is scary and he knows that he's treading on very dangerous territory all of a sudden. Hopefully his Eevee is too distracted by Katsuki's to notice how the atmosphere between them has changed.]

I know, but- a lot happened in the time between what you last remember and where I'm from. Shigaraki was...is on the verge of taking out the entire city and everyone else with it. I couldn't just stay back while he bore down on us, and you didn't either! You came with me! That's why...

[That's why Katsuki was able to take that hit at all. He was there too. Though...it was more like Katsuki came along because he knew Izuku was going to do something stupid, and sure enough...]