Actually, that is one of the most worthwhile quests, as is written, you get a random OA scroll which can be worth 1m-4m+. With only one of the rewards being worth 1m and 3 of them 4m, your chance to get a 4m scroll is 50%. Even if you spent 10hrs on that quest, it would be very much worth the time for a low lvl.
Tip: The best floor for drum bunnies is 57th floor