If a monster “cannot attack you” does that prevent it from using burst attacks that would include you?

Question

I have a scenario that occurred in our recent game. The Cleric used the 17th level encounter power Enthrall which states on hit:

Until the end of your next turn, the target is immobilized and cannot attack you.

The Cleric then moved into close quarters to effectively stop the creature from making burst attacks affecting other party members.

On the next turn the party rogue dealt a killing blow which is where the issue occurs.

As a free action when reduced to zero hp the creature makes a close burst 20 attack.

So, has the Cleric made a tactical masterstroke stopping the creatures "death throes attack"? The Enthrall effect only lasts a turn so arguably it's good fortune for the group. However, is it a little overpowered to stop an effect from the death of an enemy?

Answer 1

Overpowered or not, it was stopped correctly.

Choosing Targets, PHB 272

Many powers allow you to target multiple enemies. Each of these enemies must be an eligible target.

Using its death rattle power would require the creature to attack the cleric, but it cannot attack the cleric, so it cannot use the power.

Answer 2

It is probably not prevented.

It may depend on the monster, but the text of the monster/ability will state what the target is. For example, infernal wrath:

Infernal Wrath

Close burst 10
Trigger: An enemy within 10 squares of you hits you
Target: The triggering enemy in burst
Effect: The target takes 1d6 + Intelligence or Charisma modifier fire damage.

In the above instance the target is the enemy that triggered the burst. In your case, the rogue is likely the one that triggered it. Therefore, if the power is as above, the rogue would be the target, not the cleric, which is valid It would also mean it's possible for the cleric to be included in the blast, even though it isn't the target.

If the wording of the close burst is that it targets all enemies, and the cleric is included in that list, then it cannot activate.