A big fan that can push enemies away from the base and can also be used to clear the ash for visibility purposes
I think this is a little difficult to pull off with the current systems for the ash and enemies, and i dont understand how it would be a usefull/fun feature ingame, so i doubt this will be added ( may be possible through mods though)
As Hab already said, and also why not use turrets to get rid of enemies? It’s even more effective than fan that just pushes them but doesn’t prevent COGs from firing at you