"The bank robber crosses the street with a pistol in his hand and heads for the branch. He pushes open the door and ..." This is the prelude to the bank robbery in your script? Excellent! But have you also considered why the bank robber holds the pistol in his hand while he crosses the street? You probably mentioned the weapon to show that the man is dangerous and to build up tension. But would it not make sense to keep the pistol hidden and only bring it out when he opens the door so as not to give himself away?