Sorc masteries and fire damage.

[Brista]

Now, firstly I might well be wrong here but this is my understanding:

Pack of monsters

A A A
A B A
A A A

Sorc shoots monster B

Now let's say for the sake of argument they are all within the splash area

The sorc's damage as listed on her items is
100 physical
100 lightning
100 fire
25% crushing blow

She has sufficient mastery to add 200% fire and lightning damage

Monster B takes
100 physical adjusted by the usual multipliers - Dex, Might etc
100 lightning * (100+200 mastery bonus)% = 300 lightning
100 + 2-4 for lvl 1 exploding arrow fire * (100+200 mastery bonus)% = 306-312 fire
25% chance of crushing blow

Monsters A take
100 + 2-4 for lvl 1 exploding arrow fire * (100+200 mastery bonus)% = 306-312 fire
25% chance of crushing blow

Now every time the shot pierces a new monster becomes Monster B, any around him close enough to be caught in the splash take the Monster A damage (again)

As I say I'm not entirely sure that's right