Yesterday I was doing a normal Naxx-raid consisting several alts and three Naxx-virgins. We did really good (except me who ran around clueless with my fury-warrior. He has been a tank since the invention of the shield so I use that as an excuse ;)), but what really surprised me though was when Heigan the Unclean hit the floor and The Safety Dance achievement flashed on the screen!
This is an achievement I do not even have on my main who has been there many many times with raids consisting of more Naxx-experienced players. Nicely done everyone, and especially the new ones!