I doubt the zerker reflect reflects ground AOEs. Its probably just projectile atks like Fireball & Flame arrow like MCA did.
Also Mystics cant lower MP down to 0. Its a debuff & since debuffs cant be stacked all we can do is lower it once while Sakers lower it the rest of the way.
Yeah almost 1k debuff ... makes u wonder if a Dev even saw a lvl 79 char max mana average and realized how retarded this skill is