Shang let go of the tail.
BANG!
The tail slammed into the ground, destroying the earth beneath it. If Shang had kept hold of the tail, his spine would have most probably been broken. At that point, he would be unable to move, which would have been a huge issue in this fight.
As the tail hit the ground, a small explosion of blood appeared below it. Shang had consumed a huge amount of life energy from the snake's tail, making it weak. Because of that, it couldn't perfectly withstand the strong impact.
At the moment, Shang's left arm was swollen with life energy, and he felt like it was about to explode. However, that didn't matter.
Just as predicted, the snake's head shot towards Shang. It would be difficult for Shang to block that attack with his sword in his position, but he didn't plan on doing that anyway.
Shang's arm pointed downwards.
BANG! BANG!