Different question on the famous power Lightning Rush (which is of course not a Dilettante power, but a standard Battlemind one):

At-Will Augmentable, Psionic, Weapon

Immediate Interrupt Melee 1

Trigger: An enemy within 5 squares of you targets an ally with an attack

Effect: Before the attack, you move your speed to a square adjacent to the triggering enemy.

Target: The triggering enemy

Attack: Constitution vs. AC
Hit: 1[W] + Constitution modifier damage.
Effect: You don’t get your normal standard action on your next turn.
I wonder what happens when there's obstacles between the user and the triggering enemy, say, an army of other enemies. The power says nothing about the user being able to move through them, nor to ignore their opportunity attacks when you try to walk around them (or that it would grant a bonus to OAs). So basically, do obstacles that would make it impossible to reach the enemy, even if he is within 5 squares of you, render this power useless?