You saw him clench his fists and growl, so that he then punched the wall, a bit of ice forming on the wall, leaving it cracked. It was rare to see Shoto angry, most likely, something serious was happening to him.

"Damn it...God fucking DAMN IT!!"

He growled, shaking his hand in pain, and walked away. Maybe you should go over there and try to talk to him, but at the same time, he scared you. Shoto was a very self kept and calm person, but when he was angry, he was terrifying.