hey,
thats my 1st report about bug/exploit and I searched for similar posts but didnt find anything similar to this. Moreover, please excuse me for my well, less skilled english, I'm still learning.
I've noticed this just a few minutes ago.
Only 10 reputation were missing to my Northrend Vanguard (-> Kirin Tor missing) achievement, so I decided to solo one mob inside violet hold as an almost full pvpgeared rogue, but they hitted me for 8k, so I just let them destroy the gate (100% shield integraty -> 0%) to see what happens next (ok its obvious what happens, but I've never seen it).
For those, who didn't fail at VH, the gate is - of course - destroyed and the npcs ran out of the instance and despawned.
As I said only 10 reputation were left so I attacked one of the caster-spawntrio with ~ 62k hp and stunlocked him, hit evasion and battlemaster and - to my surprise - the mob wasn't interested in me, the others either! They just run, well they don't really run, bit slower than normal, to the gate to despawn!
So this is on the one side a place where you can finish your reputation and on the other side loot some money / rares or greens if lucky.
Note: I killed around 8 of the mobs (nonelite, up to 12k hp) which slowed the gatedestruction so just let the event begin and sit around waiting 'til the gate is destroyed doesn't help really because you need some time to get the third portal spawned and with it, another trio.
some additional notes:
- the triospawns can be stunned, slowed, incapacitaded
- your id isnt't locked