Crossword puzzle clue "devices that prevent fumes from escaping"

Devices that prevent fumes from escaping

Prevent from escaping

Sewer pipe that prevents gas from escaping

Crack commando unit sent to prison by a military court for a crime they didn't commit, before escaping to the Los Angeles underground where today, still wanted by the government, they survive as soldi

Escaping à la James Bond, perhaps

Those escaping