Han Sen was having a hard time under the oppression of Hui Hai Feng's barrage of spear strikes. The fast-paced attacks restricted any use of his rex spike.
If he used his Dual skill, he'd have no trouble thwarting his opponent. But Han Sen was here for the sole purpose of improving his rex spike skills. As much as he wanted to, he had to forget using the Dual skill and hold strong the way he was going.
His opponent was a master spear-wielder. Delicately, the man alternated between raging skills and gentle skills, which kept forcing Han Sen to retreat.
The softer skills kept hitting Han Sen because of their speed. They came thick and fast, and with the rex spike's encumbrance, Han Sen could never guard against one of those strikes in time.