Hello, after some long time leeching I've finally found something worth posting again. I've searched for any guide regarding this but found nothing.
So in this guide I'll be explaining how to kill of invulnerable minions so you can have the boss all alone. I found this exploit when I was farming 5 NV siegebreaker and got a pair of spikeshooting beasts. This exploit works both for melee and ranged creatures but I find it much simpler with the latter.
I can confirm that this technique is working as of 19/06/2012
Here we have the pack and as you can see the minion is invulnerable and there's really no way to damage it. What you want to do is to lure the minion away from the actual elite like so.
imgur.com/N5hgZ
After luring him away from the elite kite the minion all the way to the entrance of your dungeon (you can do this pretty much whereever, you just need a dungeon entrance/exit to go through)
Step through the portal, you don't have to wait forever. As soon as you get out you can teleport back in and the mob will simply die (be careful if the mob is molten as it will still explode and you're playing on hardcore you might lose your character).
Now, as you can see from the next image I didn't kite the mob very far, but I have really no way of knowing exactly how far away the mob has to be before he will die. Kited the minions from the cat tree to the entrace
imgur.com/icfhD
Do this over and over until all the minions are gone. TIP: I'm not really sure if it works with pulling several mobs at once and if you do decide to try it, please give some feedback and let me and everyone else know.
After doing this over and over you'll eventually be left with nothing but the elite. Congratulations on whatever rares you might get.
imgur.com/knPfr
TL;DR
1. Find elite pack with invulnerable minions.
2. Kite minions away from elite.
3. Exit dungeon with minions close to the entrance.
4. Teleport back in
5. Minion is now dead, rinse and repeat then kill elite