i.e. double dps
you can ambush/sap to open on a mage or (if you sap the rogue) the rogue on an opener and they're already at a huge disadvantage
had this happen to me in a duel on my mage and I was at like 80% and resapped lol
You can't do it if the mage has shattered barrier, every time acro tried to do it with me his vanish was bugged by shattered barrier.