Really, there was no choice at all.
Harry ran from the room.
Out in the tunnel, he found a massive horned creature standing with its back turned while Jena launched herself at it. She flew like a wild-woman toward the beast, punching it in the face as she drew near.
The Overseer stumbled backward.
Unfortunately, Jena didn't understand the nature of this conflict. It was clear by the way she fought that she saw this creature as a single discreet enemy. Knock it senseless, and the Overseer would be out of commission.
No, the Overseer's consciousness existed within the neural networks that permeated this entire facility. This hulking monstrosity was just an automaton, a pawn to keep them busy while Slade activated the Key's primary function.
Slade was the real enemy, but Harry couldn't
