As I said before, think about the composition of the room. There's a huge central platform, then segmented pathways in 8 directions. . . and the room fills with poison periodically. Why would you tank it anywhere but the center? Sure you'll want it to FACE north - this is assuming your Alliances position themselves (initially) West (A), South (B) and East (C), but why position yourself (as the main tank) in an area where your field of movement gets restricted by poison, not to mention creating a situation where (one would assume) the skeletons will move in a straight line for the dragon. . . off the main paths and into the poison? That'd be a nightmare for your melee DPS, and effectively your healers as well.
