Velassra, are you doing this in heroic or are you leveling and doing it in normal?
I originally had some issues with this one but after some advice here, it becomes are really easy badge run.
A point on the last boss, if you stand around the edge with your toons spread out, it make the fight very easy. I ignore the spikes and just heal through the damage, my very first try on him got me the achievement for under 4 minutes, only thing that slows this fight is the burrowing, otherwise pretty simple.