Shouldnt the taunts give you an additional 20% to "catch up"?
People used to beleive that threat copies put you 1st in threat list with a 20% lead, meaning your threat would be : Threat = copied_threat * (1 + 20/100).
Tests indicate the lead is not +20%, but +785% (plus about 15k for Frey The Edge). Basically if you Engage/Challenge/FtE a mob that is down to 90% health, it is extremely unlikey that you will lose aggro even if you do nothing.