Commando Cody (picture above), Joan and Henderson are trapped in the laboratory by Graber and Daly, who flood the ventilating system with a deadly gas...

A literally gasping ending to this episode. How on earth do they escape?

Options:

1) A bird fly's into the closed window, breaking it. With fresh air in the room our heroes regain consciousness.

2) They all die. Nothing happens in parts 11 and 12 of this serial.

3) Police, summoned by the ringing alarm bells, break into the room seconds after Cody loses consciousness. Our heroes are all pulled to safety.

4) Graber and Daly have second thoughts. they return to save them.

5) Nothing on this list happens.