Maybe because before you had time to really react to the poor girl getting her throat slit, you are treated to a blonde kid's heart exploding in his chest, his eyes getting pulled out and then being shot several times?

What makes it all the more evil is how nice and polite the poor kid is: makes his horribly brutal, undeserved death all the more funny.  Though the way the CIA guys casually shoot the other boy in the back and slit the Latina girl's throat is pretty sociopathically evil too.