Sumi can be forgiven for not knowing that Sakuya is a borderline misanthrope, given she's never properly met the woman before. The number of humans Sakuya is fond of can probably be counted literally on a single hand.
WAIT, WHAT ARE YOU DOING!?
Yes, it's just as you said.
I am a BRUTE, after all.
THEY'RE ALL MAKING FACES FAR TOO DRAMATIC FOR A MERE MARSHMALLOW!
I didn't know you're the type to hold a grudge like that! I'm sorry!