real life cliffhanger

In the final scene of Captain America, Lorna Gray is held captive in a glass tube where poison gas is being pumped in to make her into a mummy. Lionel Atwill stands by with a smile, telling her that Captain America will arrive too late to save her. Of course, the good Captain arrives on time and a furious fistfight ensues. I'm not sure what the vapor fumes were that they used, possibly dry ice. Adrian Booth told me that after the scene was shot, they had a difficult time unscrewing the bolts that held down the glass tube. She said she almost passed out before they got her out.