I did this with my Warrior (4/5 S1 + S3 Honor Bracers + S1 2H Mace and some blue stuff), possible for me in 5 pulls if everything works perfect - 10 minutes (a blessing of something is useful for that ^^), first pulling the whole bottom area including the hallway at the beginning (and hopefully not getting slowed down too often with frostbolts - if i get slowed down too much, i have to cancel and just kill what i already pulled together), pulling the whole bunch into the hallway to get the casters in melee-range and then cleavin' and whirlwindin' the hell out of them!

same for the top floor in one run if the frostbolts dont slow me down -> third pull in the cathredral itself (all the mobs directly on the way to the boss), fourth pull all remaining mobs before the boss and with the fifth pull i get the boss himself including all remaining mobs in both corners - without being an undead warrior i would have to use a lot of consumeables but cannibalize 4tw

got my toons from 20 to 40 in about 23-27 hours real time or something, you really stop counting the hours and try not to fall asleep at least i tried not to fall asleep