Severus kept his gaze on the battlements outside the Tower as he wove the start of protective wards wordlessly and wandlessly. He was no fool to trust a fellow Death Eater, no matter what the circumstances. His lax inattention the previous year and caused him to be backed into a corner and from there to the Unbreakable Vow. He would not make such a mistake again.
"A wise move," he said, still outwardly calm and collected. "The students do tend to be quick to leap on anything they may perceive as a weakness. The Slytherins are the most subtle about it, of course, but all the Houses do it." He made a small sound of amusement. "It does provide the most entertaining opportunities for detentions."