All of us submission wrestlers have been in a position where we go for an arm bar from the mount postion, only to have our opponent grab their own hand to prevent the extension. In Mixed Martial Arts we would just hit the opponent in the face. Here is another answer..
As Kim goes for June's right arm, June grabs her hands together to prevent the extension. Kim reaches her right arm through June's bent right and grabs her own left wrist. With her left hand Kim grabs Junes right wrist.
Kim pulls upward on June's arm and leans tot he left. This creats a space between June's arm and her own chest.
Kim slides her right foot through the opening she created by leaning earlier.
Kim inserts her left foot through June's arm and over Kim's own right foot.
Kim extends her legs forward as she leans back and pulls on June's arm.
When muscle fatique and leverage kick in, June has no choice but to leg go and get caught in the arm bar