Was fairly easy.
Gear: Immortal, Regen
Fully booked.
Health: 70k, Defense: 3.7k, resistance doesn't matter, low accuracy is actually better.
Speed: 180 (there's a lot of wiggle room on 90, on 50 you need exact speeds. 178 is minimum I think, can go over 200).
Masteries: Need whirlwind (+6 speed per enemy killed, up to 18). Any other skill that helps out damage is nice just to make the run slightly quicker.
Team: Ursala lead for 24% aura, and Crimson needs to kill 3 enemies in the waves to max out his speeds. This is actually easy as he can solo wave 2 with his a1 with zero issues if you need him to.
Final boss: very important, need the rest of your team to die during wave 2, or they'll screw up the timings for the final boss. If the dreadbombs TM is full, use A2. If you have 2 bomb debuffs, use A3. If you have only 1 bomb debuff, or 1 bomb debuff and 1 hp debuff, use A1 even if your health is looking low, you'll survive somehow.
My team was ursala lead (with her revive locked out), ninja, and two coldhearts. anything squishy enough to die before the boss is all you're looking for, and like I said, crimson can solo wave 2. Just make sure she gets 3 kills.
Now, paying attention to dreadbombs TM, and your buffs for 20 minutes or so was the real challenge.