[Warlock] Servitude Sacrifice bug

Following our earlier post about choosing Soul Link, sacrificing your pet and swapping to Sacrificial Pact for a free +20% health buff, I've tinkered around a bit and found one of my own.

If you choose Demonic Servitude and sacrifice your doomguard/infernal and swap back to Charred Remains, you'll have either a free interrupt or another AoE stun ontop of Shadowfury for use.

Instructions (same as Zizzzzy's method):

1. Pick Demonic Servitude and Grimoire of Sacrifice as your talents. 
2. Sacrifice your doomguard for an interrupt or your infernal for an AoE stun.
3. Swap your tier 7 talent back to Charred Remains/Cataclysm.
4. Profit.

Hope this is clear enough! Not as big as a +20% health buff, but it still counts. Right?