He places a link between two players that causes them to take heavy ticks of damage if they are close. Because you are only one person, he links you to nobody and you simply take the ticks of damage and die. You may be able to solo it if you have your companion out. The companion won't be able to do anything because it will be perma-stunned by the boss, but the link can still be put between players and companions if I remember correctly. Just spitballing here, could be totally wrong.