Erik has no taste in music so he doesn't recognize the tune. He's a little preoccupied right now with the rest of it anyway.

"Stop that you little shit!" he snarls as the first stab lands. He's had far worse for pain, so it isn't that which makes him hiss but the anger of yet more blood stains on this suit. And holes! It was expensive.

He struggles against the invisible force holding him, puts all his strength into it just as the knife goes into his hip but, still, there's no give. FUCK! Out of patience, insulted by the very idea of anyone keeping HIM on a leash, he gives into his primal instincts and snaps his jaws at Klaus's face.