Did this flash point halfway (didnt get to end, stopped at mid boss) before Beta ended, you definitely need a healer for this.
Tip: For the mid stage boss encounter, stay beneath the robot.. Like all bosses, it is immune to stun/incapacitation.
Going out of its bottom renders you zappable by a very painful laser lol.
Towards the end of the fight (approximately 1/4 life), many mini robots will spawn and attack.
Best to use ur AOE stuns/attacks at this pt to stun them while focusing on the main guy. Once he dies, all will die.