(need confirmation, I was bored and thinking of things to do)
Player 1 creates game at the waypoint outside of the manor.
Player 2 joins game
Players 1 and 2 enter the manor, clear the initial pack.
Player 2 begins to leave the game immediately after the initial big pack is down, immediately resumes game and clears the initial pack again and then leaves, resumes the game again and waits for player 1 (also looks for enlightenment shrine next to the manor entrance)
Player 1 quickly runs down the stairs into the maghda pack, new checkpont and quest turn in.
Player 1 leaves the game and changes his quest, starts game and then joins Player 2
Player 2 and Player 1 clear the room and this time Player 1 leaves while Player 2 (hopefully with the shrine buff) clears the maghda pack and turns in the quest yatta yatta aka they change jobs, rinse, repeat.
oh well