Herc can absently hear Tendo and Chuck and Stacker shouting in the control room, can sense some kind of commotion happening down on the floor, but he's being pulled along with Mako into her memories.

He has enough faculties left to try to reassure Gipsy first, though. I'll try to get her out. Fight this, Gipsy. Do not let her fire that cannon—

And then down he goes, into the deep recesses of Mako's mind. He's known the girl for a long time, actually, almost since Stacker rescued her. They fought alongside each other when the Jaeger program was in its infancy, so Mako and Chuck were often thrown together to keep each other busy while their parents discussed strategy or trained or whatever. So he knows instantly what she's reliving.

He still tries to stop her, though.