The description of this power says: "When using this power, the adept can ignore a single situational negative dice pool modifier of a value up to her Magic attribute. This power requires a Complex Action to activate and maybe be combined with the Adept Centering metamagic." So far so good, but what exactly does "single situational" modifier mean? Do they mean from one single source (like: the last shot you received that caused 3 boxes of damage, but the next shot that caused the same amount of boxes is another "source") or one single kind of source (like: i have 2 spells that need to be sustained, so SUSTAINING would be the single source)???

And one other important thing: how LONG does this power last?

A visibility modifier, range modifier, running modifier, recoil modifier, sustaining modifier, wound modifier...those are what come to mind. I'd figure any line item listed on the attacker or defender modifier tables would be eligible to be ignored as well.

Digital Grimoire p. 18?

I assume the single situational dice pool modifier refers to any discrete modifier.

So, since wound modifiers are applied as single modifier at the time of the dice roll, the actual way you acquired those boxes of damage shouldn't matter for that particular modifier.

e.g.

accumulating 6 separate 1 DV Physical wounds should not make a difference to accumulating a single 6 DV wound for a later test. The easy reason being what a load of book keeping.

Compare
Attr + Skill + Wound Modifier
to
Attr + Skill + Wound 1 + Wound 2 + wound 3 + Wound 4

For Sustaining, same applies. Sustaining two spells, then that's a -2, sustaining 3 spells, then -4

I'd go with
Att + Skill(Or whatever the two pools are) + Wounds + Sustaining + whatever
and you choose which of those, wounds, or sustaining, or whatever you will negate.

Once powers are on, they stay on. (Though I'm sure someone will point out if you 2walk into a mana void they might go off, in which I point out that I'm a void rating +X level adept and stick my tongue out.)

Basically what DireRadiant said. Although not what was asked, I feel I should also point out that it does not 'reduce a single negative modifier by your Magic', but 'ignore a single negative modifier of up to your Magic'. In other words, if you have Magic 5, the power will not affect a -6 Blind Fire modifier at all.

DireRadiant, I agree that the wound modifier is a discreet modifier that is calculated based on the total wounds, rather than a separate modifier for each wound. That's pretty clear from the text. The modifier for sustaining a spell is not defined so clearly. Throughout the texts, the reference is to -2 for each sustained spell. That sounds more like a discrete modifier for each sustained spell.

It's one power point for the power, so I would tend to be more liberal in favor of the player. It would also only apply for a Mystic Adept who can both cast and sustain spells (Usually, I think an adept has a way to get a power to sustain spells too), so I would tend to lump the multiple sustained penalty into a single mod for this power.

A fun idea is to combine Berserk, Heightened Concentration, and Living Focus. You can get a friendly magician to cast a buff spell (Firewater Aura is a favorite) on you, which you sustain, and then ignore the penalty as you go into a berserk rage at the enemy.

Hey! I play an adept who has two of those three. But instead of Berserk, he has .... Analytical Mind. You should see the opponents tremble at his logic, fired at them at 4 syllogisms a turn!