Few things to add
At 42, start doing BRD and for best XP dont run the whole thing, just these areas: Dark Iron Highway, Detention Block and Arena area. For Arena area, just park your toon inside the ring and run around the outside and above. Only run the whole thing when you want to finish quests.

On loot, i do Master loot and set the high level running the instance as the master looter. Both low level set pass on loot, this way you can just sent the loot direct into the bags of low level and you dont miss anything if you want to loot.