All bases have a weakness to flyers... the problem is, there are so many of them that if they spawn close to the base, they will take out a tower... its just part of the game... There is no hero that can auto attack them fast enough to kill them all... its a proc that usually takes them out.... so sometimes you need to wait for proc.... wether its molts, Vlads, or SB, orcs, DK, Immort and so on.... Most upper waves are gonna be like this... there is nothing you can do... you just have to hope that you can survive the hero attacks that come once the tower is down... sometimes you can, sometimes you cant.... that is where the luck is involved.... if PD is right in the middle of a wave on R and the tower goes down, he is probably not gonna survive.... you may still win the game, but will be harder with less heros....