Yeah but the thing is he made Lian sad
It wouldn't get through to his head if he did it to anything else
At this point if he messes up Mr's stuff he just bottles it up
The reason he holds it in actually is BECAUSE of how made he was at Mr for being mad at Will for biting him. He just said to himself "there's no point in getting mad at him. I can't get through to him, and it will just make Lian mad at me."
He'd freeze up, with 3 thoughts in his mind:
"I never would have thought this would happen."
"This is so out of character for him. He's never been so angry."
"At least he can get through to him."
then after screaming his lungs out for a good thirty minutes, he'd just walk over to Mr and say something like "come on, let's go before i lose it again."