You also have to remember that some people dual-box or run even more instances of the game and sometimes set something like this up to where he can have several characters on at once (with multiple accounts usually) and just press the pre-made macro on all the mages casting the blizzard II etc after he has gathered all the mobs together. Its not hard to run a few instances of this game at the same time, especially if you lower settings. I know of some who have done it in 1.0/2.0 to essentially quest 1-50 with 1 main character and more mainly on follow while in a party to get all exp from mobs and just cycle through the characters to complete quests at the same time giving multiples of the rewards.