Almost everything that Serribon had experiences after the night they shared Emperor Crocodile with Gina had been a fabrication on the part of the demon. In truth the negociation had not been nearly as confrontational. The greatest obstacle was a lack of trust, but Vargas had a plan. Through storytelling, he essentially dared Gina to make a sacrifice to prove her commitment to her duty by offering his spellbook as collateral. Alas, the demon had decided enough was enough. They were too close to Benedict. So it finally assumes direct control, and tries to kill Serribon outright. But it is too slow. They are able to subdue and bind Serribon before the demon can kill him with his own dagger.