Just to be sure to avoid flaming, I'd like to note that, unlike Zapdos's shield, the damage you deal to Raikou's shield doesn't "go over". If he has, say, 50 HP on the shield and you deal 80 damage, the other 30 damage won't pass over to Raikou himself. You will just break the shield. So when I say that the cast is interrupted if Raikou takes even 1 point of damage after the shield is broken, it means that someone must hit Raikou AFTER the shield is shattered.