Heisuke was definitely infuriated after Shuuya revealed everything to him about Kousuke's actions.
He was also in disbelief. He didn't expect that his former friend really orchestrated such a play right behind his back.
After the initial wrath and incredulity, Heisuke's mind became numb. He was too mad, too surprised and too speechless.
Heisuke didn't dare to go back when his mind was still in a messy state. He knew that he couldn't hide the chaotic feelings from showing on his face. Certainly, his mother and Hisaki would notice and worry about him.
If not for Shuuya having the emergency call, Heisuke might ask to stay at the pottery kiln until its closing time. But, luck was not on his side.
"Thank you for what you've done, Shuuya. I really... really appreciated it."
Heisuke left the kiln with those words to Shuuya. His friend kept reminding him that he could ask for help any time he needed it. Heisuke was once again grateful to Shuuya.