 CONT: When Gerry and Sewell have broken in in Mr. Cairds house,  its Sewell who says, "Thats Mr. Caird! This is Mr. Cairds house!"  when he hears him entering the house. But since its Gerry who has  met Mr. Caird in school, and is looking for a payback, Sewell  couldnt have possibly known who Mr. Caird by his voice.