Ok, so I was doing some RBGs again yesterday on my decently geared resto shaman (altho 483 geared, "only" 8300 resi, since I have quite a few int and spirit gems and not pure resi). We were at around ~1950 MMR and faced another team with also around ~1950 in Gilneas.
First zerg at waterworks between the teams:
Running in behind my team, doing some healing, dispelling and hexing some, all of a sudden I get focused and I drop immediately from around 60% to 0%. I was like "WTF?!", cause I didnt even use my big cooldowns and first dmg income was rather slow.
Checked my combat log and saw that I got hit by a 210k starsurge.