Haven't done it yet but there appear to be 6 named in the instance. You chat with Kurn to trigger the event. One by one the named will go live, when you kill one the next goes live, the order is random. While this goes on adds will spawn, All but the golems are mezzable.
The last mob to go live is the Champion, killing him wins the event. Essentially kill the named, kite the adds, when Champion is dead clean up the adds.
Champion of the Tower
Casts: Tower's Decree, a 10 second a/e stun, & Tower's Edict
Mundunugu Rathiss
Casts: Pox of Rathis, Rathiss' Torrent of Poison
Reaver Lord Thersith
Casts: Wave of Darkness
Srith the Iron Fist
Casts: Srith's Disabling Shout, an a/e FD.
Torkis the Darkscale
Casts: Darkscale Leach, Torkis' Pyrocruor