The expression 'seeing red' is extremely apt for describing Eric's current mental state. The sheer bloodlust that is so carefully kept in check under normal circumstances holds full sway over him, combined with the consuming rage at both the Master and the Doctor - and the Doctor's innovative little sunlight toy, which is the only reason he hasn't slaughtered them both, and all the Extras besides.

Still, Godric's weak protest manages to reach him somehow, through the haze. Eric practically snarls in response, flitting over to Godric's side and leaving the Doctor. The sight of his maker's injuries only enrages him further.

"Godric, this cannot be allowed to stand."