This is one of my favourites scenes of Sieun and Suho in season 1; like Sieun doing something for Suho. Giving him some warm broth that, maybe, wasnt that deep for the writers but you can actually see how, despite the cold environment he grew up, much warm and kind of a kid he is. And you can actually see the surprise in Suhoβs face because no one other than his grandma did something so caring and so kind at the same time.
They are just two lonely kids who are now discovering what friendship, love, relationships means and how good is having someone who just loves and cares about you.