If a battlemind and her cleric companion are the target of two attacks by a Yuan-ti Anathema, and the battlemind uses lightning rush, what happens?

Question

Situation: a near-epic Battlemind and her Cleric friend are standing adjacent to each other, 3 squares away from a Yuan-ti Anathema with no intervening cover or interesting fiddly bits.

The anathema uses Double Attack, which:

The yuan-ti anathema makes two slam attacks, each against a different target.

and targets the battlemind and the cleric.

The battlemind then uses her II to invoke lightning Rush and hits with her augment 2.

Does the battlemind then:

1) Get targeted by double attack once or twice? 2) Get one or two attack rolls?

Would there be a difference if the Yuan-ti used bite against the cleric, or moved and used horde of snakes?

Related.

Answer 1

The battlemind gets her attack and then faces one reprisal.

The sequence of events for attacks is laid out on pages 214-215 of the Rules Compendium

1. Choose and attack power
2. Choose targets
3. Make an attack roll
4. Compare attack roll to defense
5. resolve hit or miss
6. Repeat steps 3-5 if more than one target

Step 2 is not repeated, nor is there any requirement to recheck if the target is valid after step 2 so the sequence for your scenario is (simplified):

1. Yuan Ti declares attack
2. Yuan Ti targets the battlemind and the cleric
   1. Battlemind interrupts with Lightning Rush, triggered from the cleric being targeted.
   2. Battlemind hits and becomes the target of the triggering attack. (She is now targeted twice)
3. The Yuan-ti finishes his targeting phase. Unfortunately he cannot change his targets and now the stated condition (each against a different target) is violated and one attack is lost. This is from the Interrupt definition:

(acts) before the trigger resolves. If an interrupt invalidates a triggering action, that action is lost.

The example Interrupt given in the Rules Compendium (pg195) works the same way. Shifting away as an Immediate Interrupt prevents the attack and the attack action is lost.

For the rest

• Since one attack was invalidated, there is only one attack left and only one roll.
• If the Yuan-Ti used his bite attack, the battlemind would become the target of both the primary and the secondary attacks as Lighting Rush states "become the target or the triggering attack" and the primary hit says "yuan-ti anathema makes a secondary attack against the same target.
• I understand the Horde of Snakes case to be a subcase of your [previous question]. If that isn't true, please illuminate me. (Not saying I agree with the answer to that question...yet.

Answer 2

From WotC customer service, Twin Strike attacks can have their targets selected at the point of making each of the attacks, rather than all targeting happening up front. So one of these happens:

A) The Yuan-Ti starts the Double Attack with an attack on the Cleric.

• The Cleric is targeted with an attack so the Battlemind triggers lightning rush.
• The Battlemind makes her attack.
• The triggering attack happens with the Battlemind as the target
• The Yuan-Ti may now attack the Cleric (a target who is not the Battlemind) with the 2nd slam attack.

B) The Yuan-Ti starts the Double Attack with an attack on the Battlemind.

• The attack happens with the Battlemind as the target.
• The Yuan-Ti may now attack the Clerc with the 2nd slam attack.
• The Cleric is targeted with an attack so the Battlemind triggers lightning rush.
• The Battlemind makes her attack.
• The triggering attack no longer has a valid target as the Battlemind has already been attacked, and so fizzles.

Answer 3

The Battlemind takes one attack and gets a reprisal. Here is the order of actions that invalidates the second attack:

• The attack is made targetting both the battlemind and the cleric.
• The battlemind triggers lightning rush
• The battlemind makes his attack
• The battlemind takes the attack intended for the cleric.
• The other attack is lost because the battlemind is no longer a valid target. (per the fact that immediate interrupts can invalidate an action if it is no longer a valid action)

I think this has the best support from the RAW that I can find at the moment.