Summary (a quick, 2-3 sentence summary): I've been thinking about this for some time, but lets give the boiler a defensive smokescreen. It would give the undefended Boilers a chance to run from marines, or ward them off, depending on what type of gas they use. Most likely nonlethal, but an option for lethal would make sense, just costing a bit more. It makes sense for the Boiler to have a feature if it can launch globs of acid, and I know the boiler has an acid spray, but once marines see it, they'll know and will try and chase regardless. But a smoke/gass screeen would be harder to deal with, and add some sort of new play style needed to deal with them.
Benefits (How this will benefit the server and game as a whole): It would give Boilers a chance to escape pursuing marines.
Details (Description of how you think this would work, the benefits, etc):It would bring new tactics to the field, and add a more effective form of escape to the boilers.
Implementation (Optional, if you have an idea how to implement it): I wouldn't know this one.