Here's my way of doing it:

1. Clear the area
- As you approach Ahune: 2 groups of naga, 1 group slavemaster, 1 group lobster
- Behind Ahune: 1 group of naga, 1 group slavemaster

2. Melt the Icestone
- Make sure the shaman summoning isn't left behind because of a slip

3. Leave Shammies at 20 yards, DPS down big elemental
- If the ice break is forming under the shammies, just move them up with autofollow
- It shouldn't take more than 1 ice break to down the initial elemental

4. Drop healing stream totems, magma totems on non-icy ground
- Run circles around your magma totems for a couple minutes, redrop as necessary

5. Ahune retreats
- DPS him down

6. Loot and repeat