AoE's with Durations...

[Rubik]

...How do they work, exactly, when you move through them?

Let's say I'm using Spiked Tentacles of Forced Intrusion (http://www.d20srd.org/srd/spells/blackTentacles.htm) or Energy Wall (http://www.d20srd.org/srd/psionic/powers/energyWall.htm).

For the tentacles, if you resist the spell on your first roll, are you immune for that round (other than half-movement)? I assume so, but I would think you'd have to make additional grapple checks the farther you moved, especially if the area was extra-wide (such as if it were Widened). What if I ran in and out of the area of effect, then back in again? Would I be re-grappled?

On the wall, let's say it's covering the entire length of a 100' x 10' hallway, and I want to run down the hall. Do I only take 2d6 damage on a failed save, plus-or-minus a couple of points? What if I run headlong into the wall from the side, and pass through each zone on the same round? Would I take 1d6+2d6+ML damage? What if I ran back and forth between zones? Would I make multiple saves and take the damage multiple times?

And are there any rules quotes to back all this up?

Thank y'all in advance.

[Shadowknight12]

Subjects, Effects, and Areas
If the spell affects creatures directly the result travels with the subjects for the spell’s duration. If the spell creates an effect, the effect lasts for the duration. The effect might move or remain still. Such an effect can be destroyed prior to when its duration ends. If the spell affects an area then the spell stays with that area for its duration.

Creatures become subject to the spell when they enter the area and are no longer subject to it when they leave.

Underlining mine. That's the important tidbit. You become subject to the spell when you enter the area and are no longer subject to it when you leave. If you do not leave the area of the spell, you are continuously being subject to it, no matter how often you save. In the case of the Spiked Tentacles of Forced Intrusion, you get grappled again the next round. In the case of the Energy wall, you take damage every round (though in both cases, you can avoid the effect as normal if the tentacles fail their grapple or halve the energy damage if you succeed on the save).

EDIT: If you run back and forth across the wall, you get a save for every time you enter the damage area and one for every turn you remain in it. It's also Ref/Fort half, so you ARE taking damage every time you do so (unless you have Evasion), you're just saving for half.