In game " World of Warcraft " Cataclysm 4.3.4 " you can enter "Dungeon Journal " with (Shift+J) - Cataclysm / Dungeon / End Time /"Echo of Sylvanas " and read "Blighted Arrows" what Boss do . I am to lazy to write all from there .
There is written : " Sylvanas blights the ground in 3 yard radius circle beneath random player AND LEAP TOWARD the SKY .
In "Monster-wow" the "Sylvanas "dont jump at all . She is taking random player and instantly set -50% movement speed and inflicts-35,000 Damage every 1 sec .
If you are not Mage - who can use " Blink " instantly , or Paladin who can use " Devine Shield"instantly, or Warlock who can use "Demonic Teleport " , or even Goblin it's Instant Death for YOU .
Here is Video how "Echo of Sylvanas" Should work :