I've noticed, specifically in some nuclear reactors that work by releasing plutonium/uranium through e-wall's will sometimes ignite their nuclear material before intended. One way to easily solve this problem is to only allow particles to move through a specific wall one-way and the user can change which side the particles move through similar to the way you change a fan's speed/direction. The nuclear reactor example is the only one I can think of right now but I'm sure there are more.

Yes indeed