Hmm i play my QoT alway like this.
Max Shield and Groundspikes, little Spikewave for slow and put the rest in Uproot and Compost.
Favor= Blood of the Fallen
Items= Scaled helm, gaunlets of brutality, Vlemish Faceguard, Battlecrown, Unbreakable Boots and then going for Slayers Wraps.
When you get Slayers Wraps, you will crit for 1200+ dmg on Groundspiked Towers (Only 1 groundspike
)... should be with lvl 10
So... 2 QoT should be able to kill a tower in less than 6 seconds ^^ Demigods will also go down fast.
After groundspikes you do around 300 per shot, with 2x groundspikes, i think the damage should be around 400.
so if both QoT first do Spikewave = 1000 dmg then groundspikes = 1300
If i remeber right, you have 4 shots on armorreduced DGs.... 4 autoattacks of both =3200
Thats 5500 dmg in ~7 sec without any crits with lvl 10^^ Only heavy healtstacking chars should stay alive after this. And you should easily stay alive with
Shield (but i don't think they stack) and a very strong earlygame.
Really don't think 2*Qot = Instant loss... Could be a really hard Combo if played right.
After a kill you should have enough time to rape 3 or more towers.
Ok thats massive theorycraft, but looks very heavy to me^^
Edit: if you have to play Fortress mode against 2 of this QoT... better leave instant 
Sorry 4 my english