The words, though spoken in an almost playful tone, froze Severus" blood and bones. With a bit of prodding, Severus was coerced into telling the Dark Lord who he was truly loyal to. Despite the fact that his words would probably mean his death, Severus told his lord the truth. He worked with the Light to protect Potter. He also told the Dark Lord of the vow Albus'd had him make to protect Potter.