Okay, either we are still running sims in the mirror, or Dumbledore hexed the ever loving fuck out of that cloak. Voldemort is acting like he just took an enormous dose of Bhal's.

Or.. he can't kill Harry, and knows it? It's plausible, as about a million people have suggested it that killing Harry would send him into Voldemort's horcruxen, which might be bad.. but no, there are lots of not-fatal at all ways of putting a stop to that prophecy...