He makes two sounds: one guh! when he's kicked, and another when Kaworu adds insult to injury immediately after. Neither are much of an insult or injury, but he is wounded and betrayed by a cruel angel. His face is indeed expressive, and it pinches exaggeratedly before settling to listen to Paul's question.

He could simply not speak, but it doesn't occur to him to refuse his automatic inclination to answer a beloved. He should say something harmless, some stupid little high school embarrassment, but real truths jostle for attention.

"Where my Quirk came from."

Faces lie. All Might uses his smiles to reassure people and trick his own fear all the time. Midoriya finds this difficult to do. He finds himself trembling silently, trapped within himself like a moth in a jar as he stares at Paul with eyes wide and mouth firmly shut. This is the best he can manage. A neighbor is practicing drums at this ungodly hour, but really it's his heart pounding in his ears.

He leaves the comfort of the bed and quietly pads out of the warmest room, forgetting to put on something over his T-shirt. He shivers in his cold sweat as he goes to make a round of the apartment even though he knows perfectly well that Danger Sense's range far exceeds its bounds. His body immediately misses the steady heat of two bodies tucked against it.