With Elise evolving Alba according to the plan Gordon knew that he could rely on her to produce a better result then he ever could. Realizing that he wasn't needed Gordon had struggled to come up with something he could do to help the situation. It was only a moment before he realized that what he had to do was distract and destroy.
This was going from the pot into the fire, but Gordon knew that everything else was taken care of. It was time to put himself in the line of fire and see how things went.
So here he was with [Basic Invulnerability] active and surrounded by his combat oriented Skill Tomes. The monstrous clams were reacting to his presence. Somehow they knew that he was here. Gordon could only assume that the apocalypse system was somewhere guiding the battle.