After the glass house starts to close up, Arthur grabs a chair and slams the front door. Dennis tells Arthur he is wasting his time, the house is all sealed up. After a little explaining, Arthur yells for his son. Dennis says, "You are wasting your time, this is ectobar glass." Dennis says it is shatter proof and sound proof. At the very end of the movie when the house explodes the windows are gone. How is this possible if the windows are shatter proof?