Final stage is absolute garbage for this reason.

The squads just keep running in that circle, they are stuck there. So all you can do is retreat and try again that way.

Edit: Nvm, they can actually move down on the arrow point at the right. It just took them 9 laps to do so... Thought they would approach of from below and move left or upwards. Looking at the map again I know thats not possible, but my god that was some stupid rng.

There's HUGE difficulty gap between ?-3 and ?-4. The pest tanks better and hits harder, specially last boss. I consider myself lucky because my weakest squads managed to buy time by sacrificing themself at final boss and my main hitter goes around to finish remaining pest node.

Still the one who gives 'Pass 3 rng nodes to reach the pest' idea is a devil