Had and interesting situation come up while running through some tests.

Large monster (in this case a Boss Ice Wyrm, with a hero already in it's stomach) is bracketed by two heroes both with Magic skills. A third hero covers one side, although not immediately adjacent and a wall is nearby on the fourth side.

12 3 4 5
ZXXXX The Bs at Z1/F1/E5 are blocks or walls/internal corners such that they are impassable to the Wyrm
AXXHX
BXMMXH
CXMMX
DXMMX
EXXHXB
FBXXX

At the start of the Ice Wyrm's turn both heroes play the Sparks of Pain Feat giving them both Aura 4.

The first interesting thing is wow, what a great tactic! The heroes are really able to force the Aura to do a lot of damage at great effect, especially on a high(ish) armour, stealthy monster.
The Wyrm is now in a major pickle. It cannot swallow either hero as it already has a hero in it's stomach. It cannot do enough damage in one attack to kill either hero. Thus, if it does not move it will suffer 8 damage ignoring armour - a very significant amount (in fact enough to kill it in this case). If it moves two spaces without completely escaping the aura it will take 8 damage and die.

The second interesting thing, is that if it moves one space (to A-C/1-2 or to C-E/1/2) then it suffers 4 damage and then at the end of the turn probably another 4 damage for still being in one of the original aura spaces it inhabited.
FAQ pg 7
A: If you begin your turn on a damaging effect, such as lava or a monster’s aura, and do not move off of it, you are damaged by it at the end of your turn
The Ice Wyrm will have begun it's turn on B2/D2 and after moving still be on one of those spaces, so still suffer the 'not moving' aura effect even though it did in fact move.

Does anyone disagree with the monster taking damage for still being on one of the original aura spaces?

It is clear from the DJitD rulebook that a large monster only suffers an effect once even if it occupies multiple spaces of that effect, I think this basically gets around that rule.
First, the two different aura's are really two different effects I think.
Second, the effect at the end of the turn is a different effect than the moving effect.
Third, at all times only one space of the monster is being counted for any particular effect, even if two spaces are being subjected to that effect, so the rule is being followed. Eg, if the monster moves NW, then even though both A2 and B2 are in the A3 hero's aura, the monster only takes 4 damage.

Based on your diagram, if you've ruled that large monsters only suffer for entering aura spaces and not for allowing their rear spaces to continue through them, then it looks like the Ice Wyrm can escape taking only 4 wounds, by rotating towards the lower right and then moving straight right. Though the rightmost hero could block that by standing one space lower.

Ignoring that, by RAW, you appear to be correct--depending on how you choose to rule large monsters. From previous established, we've established that the current FAQ ruling on large monsters and terrain is garbage, at least as written, so we're guessing intent at best. My recommendation has long been to ignore the ruling completely and go by earlier rules, but if you're going to try to roll with it, then I think it could be argued that only the spaces the large figure enter "count" for its movement, and so any movement counts as moving out of the hazard it started in. Unless you're arguing that the entire aura is just one hazard, I guess.

Of course, IMO, the problem here is that the FAQ ruling on being damaged for not moving is sloppy. They should have ruled that a figure that does not move during its activation is affected as if it had just entered its current location. Double-counting for a figure that moves, but doesn't move far enough on its turn seems profoundly unfair, and most likely against the intent. But it's up to you.

Antistone said:

Thanks for the answer.

I agree, it seems profoundly unfair, which is why I really didn't feel right about the conclusion I came to and threw it out here for discussion.

I figure that each of the eight spaces around each figure is an independent hazard, though from a single source - a single figure moving through each in turn would be affected 8 times, rather than once. However two heroes with an overlapping Aura would deal 8 damage per overlapping space.
Combine that with the large monster/slime rule on pg 15, coming as it does in a combination with the large monster/AoE rules, means that the large monster only suffers each 'source' once per movement even though it may cross multiple hazard 'spaces' per movement.
And ending within the same source even though the figure has moved, just because it is a large figure really does seem to go against the spirit of the rules, if not the letter.
While, I'll generally favour the letter, purely on the grounds that the spirit is subjective and differs from person to person and situation to situation, I do prefer to reconcile the two whenever possible.

And yes, "A figure which does not move during it's activation is affected as though it had just entered it's location" or something similar would have been a much better wording.