Is it possible to mod in a fire extinguisher-type item? Trucking around cruise ships that are lit entirely on fire seems like something an ultra-elite global military organization should be able to deal with.
Doesn't smoke take out fire? A simple smoke weapon might be the thing you need.
If you have a unit on fire, there's nothing to do
Because of the way unconscious units are handled by the engine, I don't think they can be on fire. So, next time one of your soldiers is on fire, get the nearest cattle prod and BRRZZZZZZT.
There's a strange behaviour to the extinguisher. It does put out fire on burning units all right, but it fails to put out fires on the ground, even if damage type is smoke & area blast.