The feat is to kill Zetta Drone within 4 waves of healing bots
this is the normal way to do it
https://youtu.be/toMZImXWEesHero spy Miyavi reporting..
My villain league did this feat with 7 people only. 1 tank, 2 controllers, 2 dps and 2 healers. Dps first kill one of the healing bots, then leave one alive so the next wave of healing bots will not sporn. Tank pull the mini robots away from healers. Dps focus on the boss. Need major dps so the heals were less than the damage dps are doing. Ignore Bat Drones as their damage is low and will be destroyed along with any area attack.
p.s. we need a strong tank.. that is the challenge