Since it would be a noisy war, then it was in both sides' interests that the battle ended as quickly as possible. Better yet without suffering much damage and injuries.
Eric was no different he wanted to finish this as quickly as possible as well. After all, his energy, strength, and stamina were dwindling and he wasn't able to continue for long.
With those thoughts in mind, he didn't waste any more seconds, and right when the fight actually started he teleported right behind Master Tegen.
Unfortunately, Master Tegen was no soft persimmon either as the moment that Eric's body appeared behind him, he immediately used all his strength, energy, and concentration to cut him in two.
After seeing what happened with Monk Tao he had been waiting and expecting something like this to happen every fraction of a second.
If Eric didn't make a move soon he would have already passed out due to the extremely high concentration and waste of his spirit power.