The poison gas is a fine edition to the game, but its a little OP. Ill be in a house, with all of the doors shut, and no broken windows (yet). No reason for anything to get through. But yet, as soon as a gas grenade hits, I start losing health. It goes straight through all solid material…even mettle, and concrete. I would understand if it came through a broken window but solid walls? Simply not possible. At least, not nearly in the volume that it comes in.
Personally, I would suggest that gas only comes through broken windows, or open doors, or breches created by the robots. And does not come through solid surfaces, like walls, and steele.