You know how on the final bridge there are four guards. Kill the first two guards and then pull the last two guards to where the first two guards were at the beginning of the bridge. Vazruden(the orc) will just sit in the middle and Nazan (the dragon) will start fire-bombing and rotating between three spots on the platform. In two of the spots you can nuke him without aggroing Vazruden. Takes a little more time but it is a lot easier.
However if you die to the dragon before aggroing the orc, the dragon will despawn but the orc will stay and you will have to reset to complete quests or get the chest to open.