There is no way, that I know, to disperse the wall once you have called it, short of it timing out, being destroyed, or leaving the room it is in. When it times out, it "seeps back to its grim origins" and there is no adverse effect. At that point you can make another one. If it is destroyed by damage, you get the negative effect plus the long timer until you can make another. The third scenario is the one that seems most bizarre, because you get this message:


The wall of flesh parts to let you pass.
With a shriek it collapses into a mass of gore behind you!


The first line is what I would expect if I leave the room. The wall should stay in place, or at the most disperse without causing the negative effect. But, the second line states that, despise letting you pass, it gets destroyed and then you get the long timer and negative effect. Is this wrong? If not, can there be some kind of command to purposely relinquish the wall and so not gain the adverse effects?

>There is no way, that I know, to disperse the wall once you
>have called it, short of it timing out, being destroyed, or
>leaving the room it is in.

That is correct.

>The third scenario is the one that seems most
>bizarre, because you get this message:
>
>The wall of flesh parts to let you pass.
>With a shriek it collapses into a mass of gore behind you!
>
>
>The first line is what I would expect if I leave the room. The
>wall should stay in place, or at the most disperse without
>causing the negative effect. But, the second line states that,
>despise letting you pass, it gets destroyed and then you get
>the long timer and negative effect. Is this wrong? If not, can
>there be some kind of command to purposely relinquish the wall
>and so not gain the adverse effects?

This is by design...from the helpfile: The flesh will attempt to defend the Necromancer from harm so long as they stay within the circle of its creation or until it is destroyed.

If you do not stay inside the wall, it is destroyed.