"he did it!"

Today just before specials I had the students drawing a picture of something they would see in the city or county and labeling it. As I came over to their table, Amari and William (my new student) were in a heated debate about whether Amari had snatched a crayon from William or whether William had said Amari could use it. They were in a "she did it!" no, "he did it!", no, "she did it!" type of cycle. The pressure apparently became too great and William's grasp of pronouns suddenly broke down, so it became "he did it!" no, "he did it!" no, "he did it!" From the expression on his face, William was trying hard to disagree with Amari, but couldn't figure out what was going wrong. Since they were agreeing, I redirected them back to what they were working on, and that was the end of it, but I've never seen anyone try so hard to disagree and be so frustrated that he couldn't do it.