Concealment Question

[Faustchen]

I've been perusing the concealment rules and I've run into some stuff that has confused me.

Specifically I'm concerned about the fact that rules seem uni-directional. They are always talking about shooting someone that is inside a foggy cloud, or dim light, or foliage or what have you.

But what is unclear to me is how the person INSIDE the obscuring "substance" is affected by their obscuring environment.

Imagine the following as a thought experiment.

1) There is a 25 foot sqare room.
2) There are two archers situated on opposite sides of the room.
3) In the center of the room there is a 5 foot band of extremely heavy fog that runs the length of the room.
4) So neither individual is IN a heavly obscured sqare but any line of sight must pass THROUGH a heavily obscured sqare.
5) It would seem to me then that both individuals have Total Concealment from each other even though neither of them is in a heavily obscured sqare.

Does this seem like the correct way to resolve this situation?

Now what if we move one of the individuals INSIDE the band of fog? Can he now see out of it clearly? Or is it still obscuring his vision?

 

[Kordeth]

If the line of sight for a character touches or passes through an objexct or effect that grants concealment, the target has concealment (see PHB p. 273 under "Seeing and Targeting").

In both of your examples, both characters have concealment.