When are bombs OK?

[misto]

i wish walls and r-walls would do more to block/channel explosions rather than the blast always being a more or less square/circular radius. for examble, imagine bomb set off in a reinforced steel hallway. the blast would at first be inclined to follow the path of least resistance and blow down the length of the hallway before pressing on the walls. but i understand that that sort of thing might be atmos levels of complexity