Smart raises the invisible shield to let Chain pass. A few minutes later, Whitaker bumps his head on the shield, which Smart had not lowered.
While at Control headquarters, Max leans against a blackboard, and the chalk-written formula transfers to the back of his suit jacket. He then goes to the airport where he tackles a woman. There are no chalk marks on his suit jacket in that scene, yet later, when he arrives back at Control headquarters, the chalk-written formula has returned to his jacket.