The first serpent's head struck Jin's location with a headbutt and the Astral Panda Cultivator was able to dodge it easily even without the use of his Maqi. It did, however, stop him from accumulating even more Maqi on a stationary spot and that was adequate for Orochi to follow up with the attack.
The head of the first serpent did not stop upon crashing into the ground and retracting itself back to its original position. Instead, it continued to chase after Jin and its speed increased dramatically like a homing missile set to kill its target.